f2fs: remove unneeded disable_nat_bits()

Commit 7735730d ("f2fs: fix to propagate error from __get_meta_page()")
added disable_nat_bits() in error path of __get_nat_bitmaps(), but it's
unneeded, beause we will fail mount, we won't have chance to change nid
usage status w/o nat full/empty bitmaps.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/node.c

@@ -2879,10 +2879,8 @@ static int __get_nat_bitmaps(struct f2fs_sb_info *sbi)
 		struct page *page;
 
 		page = f2fs_get_meta_page(sbi, nat_bits_addr++);
-		if (IS_ERR(page)) {
-			disable_nat_bits(sbi, true);
+		if (IS_ERR(page))
 			return PTR_ERR(page);
-		}
 
 		memcpy(nm_i->nat_bits + (i << F2FS_BLKSIZE_BITS),
 					page_address(page), F2FS_BLKSIZE);