xfs: enable the rmap btree functionality

Originally-From: Dave Chinner <dchinner@redhat.com>

Add the feature flag to the supported matrix so that the kernel can
mount and use rmap btree enabled filesystems

Signed-off-by: Dave Chinner <dchinner@redhat.com>
[darrick.wong@oracle.com: move the experimental tag]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index f6a0641..f814d42 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -457,7 +457,8 @@
 #define XFS_SB_FEAT_RO_COMPAT_FINOBT   (1 << 0)		/* free inode btree */
 #define XFS_SB_FEAT_RO_COMPAT_RMAPBT   (1 << 1)		/* reverse map btree */
 #define XFS_SB_FEAT_RO_COMPAT_ALL \
-		(XFS_SB_FEAT_RO_COMPAT_FINOBT)
+		(XFS_SB_FEAT_RO_COMPAT_FINOBT | \
+		 XFS_SB_FEAT_RO_COMPAT_RMAPBT)
 #define XFS_SB_FEAT_RO_COMPAT_UNKNOWN	~XFS_SB_FEAT_RO_COMPAT_ALL
 static inline bool
 xfs_sb_has_ro_compat_feature(