f2fs: code clean and fix a type error

ERROR: code indent should use tabs where possible
ERROR: spaces required around that ':'
ERROR: incorrect tab

Found serveral code type errors when review the code and fix it.
There is no function change.

Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>