scsi: fix integer as NULL pointer warning

drivers/scsi/aha152x.c:3585:60: warning: Using plain integer as NULL pointer
drivers/scsi/aha152x.c:3845:56: warning: Using plain integer as NULL pointer
drivers/scsi/qla1280.c:2814:37: warning: Using plain integer as NULL pointer
drivers/scsi/atp870u.c:750:47: warning: Using plain integer as NULL pointer
drivers/scsi/3w-9xxx.c:1281:36: warning: Using plain integer as NULL pointer
drivers/scsi/3w-9xxx.c:1293:36: warning: Using plain integer as NULL pointer
drivers/scsi/3w-9xxx.c:1301:35: warning: Using plain integer as NULL pointer
drivers/scsi/hptiop.c:447:10: warning: Using plain integer as NULL pointer
drivers/scsi/hptiop.c:457:10: warning: Using plain integer as NULL pointer
drivers/scsi/hptiop.c:479:24: warning: Using plain integer as NULL pointer
drivers/scsi/hptiop.c:483:22: warning: Using plain integer as NULL pointer
drivers/scsi/hptiop.c:1213:23: warning: Using plain integer as NULL pointer
drivers/scsi/hptiop.c:1214:23: warning: Using plain integer as NULL pointer

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>