f2fs: fix to unlock page correctly in error path of is_alive()

As Pavel Machek reported in below link [1]:

After commit 77900c45 ("f2fs: fix to do sanity check in is_alive()"),
node page should be unlock via calling f2fs_put_page() in the error path
of is_alive(), otherwise, f2fs may hang when it tries to lock the node
page, fix it.

[1] https://lore.kernel.org/stable/20220124203637.GA19321@duo.ucw.cz/

Fixes: 77900c45 ("f2fs: fix to do sanity check in is_alive()")
Cc: <stable@vger.kernel.org>
Reported-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/gc.c

@@ -1038,8 +1038,10 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 		set_sbi_flag(sbi, SBI_NEED_FSCK);
 	}
 
-	if (f2fs_check_nid_range(sbi, dni->ino))
+	if (f2fs_check_nid_range(sbi, dni->ino)) {
+		f2fs_put_page(node_page, 1);
 		return false;
+	}
 
 	*nofs = ofs_of_node(node_page);
 	source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);