frontends/va: add support for VA_EXPORT_SURFACE_COMPOSED_LAYERS
The libva docs say:
If VA_EXPORT_SURFACE_SEPARATE_LAYERS is specified on export, each layer will contain exactly one plane. For example, an NV12 surface will be exported as two layers, one of DRM_FORMAT_R8 and one of DRM_FORMAT_GR88. If VA_EXPORT_SURFACE_COMPOSED_LAYERS is specified on export, there will be exactly one layer.
VA_EXPORT_SURFACE_COMPOSED_LAYERS is desirable in many scenarios, for instance when directly importing the DMA-BUFs into APIs such as GL (as a single EGLImage), KMS or Wayland.
Signed-off-by: Simon Ser's avatarSimon Ser email@example.com