cciss: include scsi/scsi.h unconditionally

Make cciss unconditionally include scsi/scsi.h, because of the use of
SCSI_IOCTL_GET_IDLUN and SCSI_IOCTL_GET_BUS_NUMBER.

Signed-off-by: Stephen M. Cameron <steve.cameron@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>