renderer-gl: Add YUV format descriptors for P010/P012/P016

For drivers not supporting importing them directly. We use the equivalent
values to NV12 but with 16bit. The lowest 6 or 4 bits for P010/P012 are
padding and set to zero, so we can use the same subformats like for P016
and share the shader with NV12.

Signed-off-by: Robert Mader <robert.mader@collabora.com>