gallium: split transfer_{map,unmap} into {buffer,texture}_{map,unmap}, remove u_resource_vtbl
This removes the call indirection via u_resource_vtbl
, and thus removes the vtbl pointer from all pipe_resources.
resource_destroy
and transfer_flush_region
are not changed, but must check whether the resource target is a buffer or texture.
transfer_map
and transfer_unmap
are split into buffer and texture callbacks.