xfs: add fsgeom flag for v5 superblock support.

Currently userspace has no way of determining that a filesystem is
CRC enabled. Add a flag to the XFS_IOC_FSGEOMETRY ioctl output to
indicate that the filesystem has v5 superblock support enabled.
This will allow xfs_info to correctly report the state of the
filesystem.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

(cherry picked from commit 74137fff067961c9aca1e14d073805c3de8549bd)
diff --git a/fs/xfs/xfs_fs.h b/fs/xfs/xfs_fs.h
index 6dda3f9..d046955 100644
--- a/fs/xfs/xfs_fs.h
+++ b/fs/xfs/xfs_fs.h
@@ -236,6 +236,7 @@
 #define XFS_FSOP_GEOM_FLAGS_PROJID32	0x0800  /* 32-bit project IDs	*/
 #define XFS_FSOP_GEOM_FLAGS_DIRV2CI	0x1000	/* ASCII only CI names	*/
 #define XFS_FSOP_GEOM_FLAGS_LAZYSB	0x4000	/* lazy superblock counters */
+#define XFS_FSOP_GEOM_FLAGS_V5SB	0x8000	/* version 5 superblock */
 
 
 /*