ext2: fix improper function comment

Just fix a improper function comment.

Link: https://lore.kernel.org/r/20191104114036.9893-5-cgxu519@mykernel.netSigned-off-by: Chengguang Xu <cgxu519@mykernel.net>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/ext2/balloc.c

@@ -732,10 +732,9 @@ ext2_try_to_allocate(struct super_block *sb, int group,
  *		but we will shift to the place where start_block is,
  *		then start from there, when looking for a reservable space.
  *
- * 	@size: the target new reservation window size
+ *	@sb: the super block.
  *
- * 	@group_first_block: the first block we consider to start
- *			the real search from
+ * 	@start_block: the first block we consider to start the real search from
  *
  * 	@last_block:
  *		the maximum block number that our goal reservable space