cifs: teach signing routines how to deal with arrays of pages in a smb_rqst

Use the smb_send_rqst helper function to kmap each page in the array
and update the hash for that chunk.

Reviewed-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

diff --cc fs/cifs/cifsencrypt.c
Simple merge

diff --cc fs/cifs/cifsproto.h
Simple merge

diff --cc fs/cifs/smb2transport.c
Simple merge

diff --cc fs/cifs/transport.c
Simple merge