cifs: fix up CIFSSMBEcho for unaligned access

Make sure that CIFSSMBEcho can handle unaligned fields. Also fix a minor
bug that causes this warning:

fs/cifs/cifssmb.c: In function 'CIFSSMBEcho':
fs/cifs/cifssmb.c:740: warning: large integer implicitly truncated to unsigned type

...WordCount is u8, not __le16, so no need to convert it.

This patch should apply cleanly on top of the rest of the patchset to
clean up unaligned access.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>