f2fs: use existing macro to clean up some codes

This patch use existing macro F2FS_INODE/NEXT_FREE_BLKADDR to clean up some
codes.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index 72adbbf..aef7768 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -136,7 +136,7 @@
 
 	/* get node pages in the current segment */
 	curseg = CURSEG_I(sbi, CURSEG_WARM_NODE);
-	blkaddr = START_BLOCK(sbi, curseg->segno) + curseg->next_blkoff;
+	blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
 
 	/* read node page */
 	page = alloc_page(GFP_F2FS_ZERO);