fs: Do not overload update_time

update_time() also has an internal function pointer
update_time. Even though this works correctly, it is
confusing to the readers.

Just use a regular if statement to call the generic
function or the function pointer.
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/inode.c

@@ -1675,12 +1675,9 @@ EXPORT_SYMBOL(generic_update_time);
  */
 static int update_time(struct inode *inode, struct timespec64 *time, int flags)
 {
-	int (*update_time)(struct inode *, struct timespec64 *, int);
-
-	update_time = inode->i_op->update_time ? inode->i_op->update_time :
-		generic_update_time;
-
-	return update_time(inode, time, flags);
+	if (inode->i_op->update_time)
+		return inode->i_op->update_time(inode, time, flags);
+	return generic_update_time(inode, time, flags);
 }
 
 /**