iris: Set default MOCS for NULL depth/stencil/HiZ buffers

isl now uses info->mocs regardless of whether there's any actual
depth/stencil/HiZ buffers involved, so pass it a legitimate one,
rather than zero.  When we have entirely NULL surfaces, we just
default to isl's MOCS value for an internal depth buffer.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13480>
1 file changed