f2fs: fix to set atomic write status more clear

1. After we start atomic write in a database file, before committing
all data, we'd better not set inode w/ vfs dirty status to avoid
redundant updates, instead, we only set inode w/ atomic dirty status.

2. After we commit all data, before committing metadata, we need to
clear atomic dirty status, and set vfs dirty status to allow vfs flush
dirty inode.

Cc: Daeho Jeong <daehojeong@google.com>
Reported-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Reviewed-by: Daeho Jeong <daehojeong@google.com>
Reviewed-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>