graphics/mesa-devel: apply 36049d38 to Vulkan with VAAPI=off

On Intel GPUs VA-API is implemented by libva-intel-{,media-}driver but
Vulkan Video is implemented by Mesa. VAAPI in mesa-devel depends on
AMD drivers which in turn brings heavy llvm* dependency, so may not be
desirable on Intel-only or Intel+NVIDIA systems.

$ ANV_VIDEO_DECODE=1 mpv --vo=gpu-next --gpu-api=vulkan --hwdec=vulkan foo.mp4
[...]
[ffmpeg/video] h264: Device does not support decoding h264!
[...]

$ ANV_VIDEO_DECODE=1 vulkaninfo | fgrep -i decode_h264
                                VIDEO_CODEC_OPERATION_DECODE_H264_BIT_KHR

(cherry picked from commit aada4209)