f2fs: check total_segments from devices in raw_super

For multi-device F2FS, we should check if the sum of total_segments from
all devices matches segment_count.

Signed-off-by: Qiuyang Sun <sunqiuyang@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>