NFSD: Fix a thinko introduced by recent trace point changes

The fixed commit erroneously removed a call to nfsd_end_grace(),
which makes calls to write_v4_end_grace() a no-op.

Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202308241229.68396422-oliver.sang@intel.com
Fixes: 39d432fc7630 ("NFSD: trace nfsctl operations")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfsctl.c

@@ -1105,6 +1105,7 @@ static ssize_t write_v4_end_grace(struct file *file, char *buf, size_t size)
 			if (!nn->nfsd_serv)
 				return -EBUSY;
 			trace_nfsd_end_grace(netns(file));
+			nfsd4_end_grace(nn);
 			break;
 		default:
 			return -EINVAL;