xfs: deprecate BMV_IF_NO_DMAPI_READ flag

Use of the flag has had no effect since kernel commit 288699fe


("xfs: drop dmapi hooks"), which removed all dmapi related code, so
deprecate it.

Signed-off-by: Anthony Iliopoulos <ailiop@suse.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>