cifs: use %16phN for formatting md5 sum

Passing a gazillion arguments takes a lot of code:

add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-253 (-253)

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>