xfs: refactor default quota grace period setting code

Refactor the code that sets the default quota grace period into a helper
function so that we can override the ondisk behavior later.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/xfs_qm_syscalls.c

@@ -486,8 +486,8 @@ xfs_setqlim_timer(
 {
 	if (qlim) {
 		/* Set the length of the default grace period. */
-		res->timer = timer;
-		qlim->time = timer;
+		res->timer = xfs_dquot_set_grace_period(timer);
+		qlim->time = res->timer;
 	} else {
 		/* Set the grace period expiration on a quota. */
 		res->timer = xfs_dquot_set_timeout(mp, timer);