Add Missing Include Directory for ggml-cpu in whisper.android CMakeLists

[Thamster]

This PR adds the ggml/src/ggml-cpu directory to the include paths in the CMakeLists.txt for the whisper.android example.
Context:

The JNI version of whisper.android requires the ggml-cpu include path for successful compilation. Without this addition, the build fails with missing header errors on Windows.
Changes:

Added the ggml/src/ggml-cpu directory to the include_directories list in CMakeLists.txt.

Testing:

Verified the build completes successfully on Windows after this change.
Observed the following error when building without this change:

fatal error: 'ggml-cpu-impl.h' file not found

1 error generated.
  [4/6] Building CXX object CMakeFiles/whisper_v8fp16_va.dir/C_/Users/adm1n/Desktop/text-generation-webui/whisper.cpp/ggml/src/ggml-cpu/ggml-cpu.cpp.o
  FAILED: CMakeFiles/whisper_v8fp16_va.dir/C_/Users/adm1n/Desktop/text-generation-webui/whisper.cpp/ggml/src/ggml-cpu/ggml-cpu.cpp.o
  C:\Users\adm1n\AppData\Local\Android\Sdk\ndk\25.2.9519653\toolchains\llvm\prebuilt\windows-x86_64\bin\clang++.exe --target=aarch64-none-linux-android26 --sysroot=C:/Users/adm1n/A
ppData/Local/Android/Sdk/ndk/25.2.9519653/toolchains/llvm/prebuilt/windows-x86_64/sysroot -Dwhisper_v8fp16_va_EXPORTS -IC:/Users/adm1n/Desktop/text-generation-webui/whisper.cpp/exa
mples/whisper.android/lib/src/main/jni/whisper/../../../../../../.. -IC:/Users/adm1n/Desktop/text-generation-webui/whisper.cpp/examples/whisper.android/lib/src/main/jni/whisper/../
../../../../../../src -IC:/Users/adm1n/Desktop/text-generation-webui/whisper.cpp/examples/whisper.android/lib/src/main/jni/whisper/../../../../../../../include -IC:/Users/adm1n/Des
ktop/text-generation-webui/whisper.cpp/examples/whisper.android/lib/src/main/jni/whisper/../../../../../../../ggml/include -IC:/Users/adm1n/Desktop/text-generation-webui/whisper.cp
p/examples/whisper.android/lib/src/main/jni/whisper/../../../../../../../ggml/src -g -DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-cano
nical-prefixes -D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security   -fno-limit-debug-info  -fPIC -march=armv8.2-a+fp16 -std=gnu++17 -MD -MT CMakeFiles/whisper_v8fp16_va.dir/C_/Us
ers/adm1n/Desktop/text-generation-webui/whisper.cpp/ggml/src/ggml-cpu/ggml-cpu.cpp.o -MF CMakeFiles\whisper_v8fp16_va.dir\C_\Users\adm1n\Desktop\text-generation-webui\whisper.cpp\g
gml\src\ggml-cpu\ggml-cpu.cpp.o.d -o CMakeFiles/whisper_v8fp16_va.dir/C_/Users/adm1n/Desktop/text-generation-webui/whisper.cpp/ggml/src/ggml-cpu/ggml-cpu.cpp.o -c C:/Users/adm1n/Desktop/text-generation-webui/whisper.cpp/ggml/src/ggml-cpu/ggml-cpu.cpp
  In file included from C:/Users/adm1n/Desktop/text-generation-webui/whisper.cpp/ggml/src/ggml-cpu/ggml-cpu.cpp:6:
  C:/Users/adm1n/Desktop/text-generation-webui/whisper.cpp/ggml/src/ggml-cpu/amx/amx.h:2:10: fatal error: 'ggml-cpu-impl.h' file not found
  #include "ggml-cpu-impl.h"
           ^~~~~~~~~~~~~~~~~
  1 error generated.
  ninja: build stopped: subcommand failed.

  C++ build system [build] failed while executing:
      @echo off
      "C:\\Users\\adm1n\\AppData\\Local\\Android\\Sdk\\cmake\\3.22.1\\bin\\ninja.exe" ^
        -C ^
        "C:\\Users\\adm1n\\Desktop\\text-generation-webui\\whisper.cpp\\examples\\whisper.android\\lib\\.cxx\\Debug\\3id2k6h3\\arm64-v8a" ^
        whisper ^
        whisper_v8fp16_va
    from C:\Users\adm1n\Desktop\text-generation-webui\whisper.cpp\examples\whisper.android\lib

This is a minor but necessary change to ensure smooth compilation of the JNI example for whisper.android.

[ggerganov]

Thanks. Could you also enable the CI workflow for Android. I disabled it because I didn't want to spend time on resolving the build issue, but it seems this might have been the reason.

[Thamster]

The android JNI workflow appears to have been successful on my fork after re-enabling.

https://github.com/Thamster/whisper.cpp/actions/runs/12321069974/job/34391691044

Let me know if there's anything else I can help with regarding the CI setup or further testing.