ext2: fix comment on ext2_try_to_allocate()

@handle doesn't exist in ext2. Remove it.
Also, fit comment header into kernel-doc format.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/ext2/balloc.c

@@ -646,10 +646,9 @@ find_next_usable_block(int start, struct buffer_head *bh, int maxblocks)
 	return here;
 }
 
-/*
+/**
  * ext2_try_to_allocate()
  * @sb:			superblock
- * @handle:		handle to this transaction
  * @group:		given allocation block group
  * @bitmap_bh:		bufferhead holds the block bitmap
  * @grp_goal:		given target block within the group