vfs: dedupe: rationalize args

Clean up f_op->dedupe_file_range() interface.

1) Use loff_t for offsets and length instead of u64
2) Order the arguments the same way as {copy|clone}_file_range().

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

include/linux/fs.h

@@ -1749,7 +1749,7 @@ struct file_operations {
 			loff_t, size_t, unsigned int);
 	int (*clone_file_range)(struct file *, loff_t, struct file *, loff_t,
 			u64);
-	int (*dedupe_file_range)(struct file *, u64, u64, struct file *,
+	int (*dedupe_file_range)(struct file *, loff_t, struct file *, loff_t,
 			u64);
 } __randomize_layout;