[SCSI] mpt2sas: Fix possible integer truncation of cpu_count

When computing reply_queue_count (the number of MSI-X vectors to use),
the driver does

	ioc->reply_queue_count = min_t(u8, ioc->cpu_count,
	    ioc->msix_vector_count);

However, on a big machine, ioc->cpu_count could be outside the range
that fits in a u8; eg a system with 256 CPUs will end up
reply_queue_count set to 0.

Fix this by calculating the minimum as ints and then letting the
assignment to reply_queue_count handle integer demotion.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Acked-by: N"Nandigama, Nagalakshmi" <Nagalakshmi.Nandigama@lsi.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

drivers/scsi/mpt2sas/mpt2sas_base.c

@@ -1407,7 +1407,7 @@ _base_enable_msix(struct MPT2SAS_ADAPTER *ioc)
 	if (_base_check_enable_msix(ioc) != 0)
 		goto try_ioapic;
 
-	ioc->reply_queue_count = min_t(u8, ioc->cpu_count,
+	ioc->reply_queue_count = min_t(int, ioc->cpu_count,
 	    ioc->msix_vector_count);
 
 	entries = kcalloc(ioc->reply_queue_count, sizeof(struct msix_entry),