panfrost: support hw sampling of YUV textures on bifrost
This MR adds a new texture descriptor for sampling single and multiplane YUV textures on bifrost. When sampling from YUV textures, the stride /offset alignment requirement may be smaller than the usual 64-bytes, so this MR also changes that requirement for the relevant formats.
The gallium/st patch is needed for making PIPE_FORMAT_NV21
behave similar to PIPE_FORMAT_NV12
, by doing CSC in the shader but making use of the hw YUV texture sampler.