f2fs: remove an excess variable

Remove the variable page_idx which no one would miss.
Signed-off-by: NFan li <fanofcode.li@samsung.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -1204,7 +1204,6 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 			unsigned nr_pages)
 {
 	struct bio *bio = NULL;
-	unsigned page_idx;
 	sector_t last_block_in_bio = 0;
 	struct inode *inode = mapping->host;
 	const unsigned blkbits = inode->i_blkbits;
@@ -1221,8 +1220,7 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 	map.m_flags = 0;
 	map.m_next_pgofs = NULL;
 
-	for (page_idx = 0; nr_pages; page_idx++, nr_pages--) {
-
+	for (; nr_pages; nr_pages--) {
 		if (pages) {
 			page = list_last_entry(pages, struct page, lru);