multimedia/mpv: backport VULKAN+VAAPI fix for Intel

Regressed by cc87022694a6 update but the fix only helps mesa-devel.

$ mpv --hwdec=vaapi --gpu-api=vulkan /path/to/file
[...]
[vo/gpu/vulkan/libplacebo] vk->CreateImage(vk->dev, &iinfo, PL_VK_ALLOC, &tex_vk->img): VK_ERROR_OUT_OF_DEVICE_MEMORY (../src/vulkan/gpu.c:1185)
[vo/gpu/vulkan/libplacebo] vk->CreateImage(vk->dev, &iinfo, PL_VK_ALLOC, &tex_vk->img): VK_ERROR_OUT_OF_DEVICE_MEMORY (../src/vulkan/gpu.c:1185)
[vo/gpu/vulkan/libplacebo] vk->CreateImage(vk->dev, &iinfo, PL_VK_ALLOC, &tex_vk->img): VK_ERROR_OUT_OF_DEVICE_MEMORY (../src/vulkan/gpu.c:1185)
[vo/gpu/vulkan/libplacebo] vk->CreateImage(vk->dev, &iinfo, PL_VK_ALLOC, &tex_vk->img): VK_ERROR_OUT_OF_DEVICE_MEMORY (../src/vulkan/gpu.c:1185)
Using hardware decoding (vaapi).
VO: [gpu] 1920x1080 vaapi[nv12]
[vo/gpu/vaapi-egl] unsupported VA image format nv12
[vo/gpu] Initializing texture for hardware decoding failed.
[...]