vfs: fix return type of ioctl_file_dedupe_range

All the VFS functions in the dedupe ioctl path return int status, so
the ioctl handler ought to as well.

Found by Coverity, CID 1350952.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ioctl.c

@@ -568,7 +568,7 @@ static int ioctl_fsthaw(struct file *filp)
 	return thaw_super(sb);
 }
 
-static long ioctl_file_dedupe_range(struct file *file, void __user *arg)
+static int ioctl_file_dedupe_range(struct file *file, void __user *arg)
 {
 	struct file_dedupe_range __user *argp = arg;
 	struct file_dedupe_range *same = NULL;