f2fs-tools: avoid build warning

In function ‘update_extent_info’,
    inlined from ‘update_largest_extent’ at segment.c:559:3,
    inlined from ‘f2fs_build_file’ at segment.c:714:3:
segment.c:484:29: warning: ‘cur_ext.fofs’ may be used uninitialized [-Wmaybe-uninitialized]
  484 |         inode->i.i_ext.fofs = cpu_to_le32(ext->fofs);
segment.c: In function ‘f2fs_build_file’:
segment.c:495:41: note: ‘cur_ext.fofs’ was declared here
  495 |         struct extent_info largest_ext, cur_ext;
      |                                         ^~~~~~~
In function ‘update_extent_info’,
    inlined from ‘update_largest_extent’ at segment.c:559:3,
    inlined from ‘f2fs_build_file’ at segment.c:714:3:
segment.c:485:33: warning: ‘cur_ext.blk’ may be used uninitialized [-Wmaybe-uninitialized]
  485 |         inode->i.i_ext.blk_addr = cpu_to_le32(ext->blk);
segment.c: In function ‘f2fs_build_file’:
segment.c:495:41: note: ‘cur_ext.blk’ was declared here
  495 |         struct extent_info largest_ext, cur_ext;
      |                                         ^~~~~~~

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fsck/segment.c

@@ -492,7 +492,7 @@ static void update_largest_extent(struct f2fs_sb_info *sbi, nid_t ino)
 	struct node_info ni;
 	struct f2fs_node *inode;
 	u32 blkaddr, prev_blkaddr, cur_blk = 0, end_blk;
-	struct extent_info largest_ext, cur_ext;
+	struct extent_info largest_ext = { 0, }, cur_ext = { 0, };
 	u64 remained_blkentries = 0;
 	u32 cluster_size;
 	int count;