f2fs: fix to be aware discard/preflush/dio command in is_idle()

This patch adds missing in-flight discard/preflush/dio command count
check in is_idle().

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
1 file changed