xfs: Conditionally upgrade existing inodes to use large extent counters

xfs: Conditionally upgrade existing inodes to use large extent counters

Source kernel commit: 4f86bb4b66c999ad9ddcfd49fec93992eeba2715

This commit enables upgrading existing inodes to use large extent counters
provided that underlying filesystem's superblock has large extent counter
feature enabled.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>