VA_RT_FORMAT describes the desired sampling format for surface.

When creating surface, VA_RT_FORMAT will be used firstly to choose
the expected fourcc/media_format for the surface. And the fourcc
will be revised by the value of VASurfaceAttribPixelFormat.

Add vaapi_format_map support for new pixel_format Y210.
This is fundamental for both VA-API and QSV.
Signed-off-by: Linjie Fu <linjie.fu@intel.com>