frontends/va: Don't return P010/P016 as surface formats when encoding
This is almost a complete revert of 0eccd158 (!3285 (merged)), since it was a driver fix for a client bug. vaapih265enc should be fixed rather adding a workaround that breaks the logic of API, since vaQuerySurfaceAttributes depends only on config parameter, which defines the rt format.
You can verify it with vadumpcap https://github.com/fhvwy/vadumpcaps
Cc: @leoliu, @thongthai