drm/uapi: Fix modifier field mask for AMD modifiers.

The DCC_MAX_COMPRESSED_BLOCK has to contain one of
AMD_FMT_MOD_DCC_BLOCK_* and with 3 values this doesn't
fit in 1 bit.

Fix this cleanly while it is only in drm-next.

Fixes: 2cc2b456889 "drm-uapi: Add AMD modifiers."
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7607>
1 file changed