cifsd: clean-up codes using chechpatch.pl --strict

Dan Carpenter suggested to run chechpatch.pl --strict on ksmbd to fix
check warnings. This patch does not fix all warnings but only things that
I can understand.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Steve French <stfrench@microsoft.com>