[SCSI] aic7xxx_old: fix accidental logic reversal

Commit bbfbbbc1182f8b44c8cc4c99f4a3f3a512149022 accidentally reversed
the logic of this NULL check.

Spotted by the Coverity checker.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/aic7xxx_old.c

@@ -8417,7 +8417,7 @@ aic7xxx_alloc(struct scsi_host_template *sht, struct aic7xxx_host *temp)
     p->host = host;
 
     p->scb_data = kzalloc(sizeof(scb_data_type), GFP_ATOMIC);
-    if (!p->scb_data)
+    if (p->scb_data)
     {
       scbq_init (&p->scb_data->free_scbs);
     }