.github: re-enable rimage workflows

Migrate rimage build and cppcheck workflows from
sof/tools/rimage/.github/workflows/ (where they're ignored) to sof/.github/workflows/

Signed-off-by: Marc Herbert <marc.herbert@intel.com>

tools/rimage/.github/workflows/cppcheck.yml → .github/workflows/rimage.yml

@@ -9,17 +9,45 @@
 # github.com also has a powerful web editor that can be used without
 # committing.
 
-name: cppcheck
+name: rimage
 
 # yamllint disable-line rule:truthy
-on: [pull_request, push]
+on:
+  workflow_dispatch:
+  pull_request:
+    paths:
+      - tools/rimage/**
+  push:
+    paths:
+      - tools/rimage/**
 
 jobs:
+
+  # Basic build test
+  build:
+    runs-on: ubuntu-22.04
+    env:
+      CMAKE_C_FLAGS: -Werror -Wall -Wmissing-prototypes -Wimplicit-fallthrough=3
+        -Wpointer-arith
+
+    steps:
+      - uses: actions/checkout@v4
+        with: {fetch-depth: 0, filter: tree:0}
+
+      - name: install tools
+        run: sudo apt update && sudo apt install -y ninja-build
+
+      - name: build
+        run: cmake -B build/ -G Ninja
+      - run: cmake --build build/
+
+
+  # cppcheck
   cppcheck:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v2
-        with: {fetch-depth: 50, submodules: recursive}
+      - uses: actions/checkout@v4
+        with: {fetch-depth: 0, filter: tree:0}
 
       - name: apt install cppcheck
         run: sudo apt update && sudo apt-get -y install cppcheck