Fix find GPU driver dll path in windows

[whyb]

#if defined _WIN32
#if defined(__x86_64__) || defined(_M_X64)
        // find driver dll in %SystemRoot%\System32\DriverStore\FileRepository (64bit)
        std::string dllpath = search_file("%SystemRoot%\\System32\\DriverStore\\FileRepository", well_known_path[i]);
#else
        // find driver dll in %SystemRoot%\SysWOW64\DriverStore\FileRepository (32bit)
        std::string dllpath = search_file("%SystemRoot%\\SysWOW64\\DriverStore\\FileRepository", well_known_path[i]);
#endif
        if (dllpath.empty())
            continue;

        ret = load_vulkan_windows(well_known_path[i]);
#elif defined __ANDROID__
        ret = load_vulkan_android(well_known_path[i]);
#else
        ret = load_vulkan_linux(well_known_path[i]);
#endif
        if (ret == 0)
            break;

[tencent-adm]

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1 out of 2 committers have signed the CLA.

✅ nihui
❌ whyb
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[codecov-commenter]

Codecov Report

Merging #5141 (048fab3) into master (b4f2623) will decrease coverage by 0.17%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #5141      +/-   ##
==========================================
- Coverage   94.70%   94.54%   -0.17%     
==========================================
  Files         777      777              
  Lines      241608   241207     -401     
==========================================
- Hits       228813   228042     -771     
- Misses      12795    13165     +370     

Files	Coverage Δ
src/simplevk.cpp	69.56% <ø> (-14.65%)	⬇️

... and 55 files with indirect coverage changes

[nihui]

Thanks for your contribution !