pvr: Add PVR_DEBUG=vk_desc option to dump descriptor set layouts
All this change does is shift the option of dumping descriptor set layouts to runtime (instead of being dependant on a debug build). Saves on some console spam for debug builds.
Signed-off-by: Matt Coster <matt.coster@imgtec.com>
Reviewed-by: Frank Binns <frank.binns@imgtec.com>