mvsas: always iounmap resources

In case pci_resource_start() or pci_resource_len() reutrn 0, mvsas_ioremap
returns without doing an iounmap() of mvi->regs_ex.

Found by the cocinelle tool.
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

drivers/scsi/mvsas/mv_init.c

@@ -338,8 +338,11 @@ int mvs_ioremap(struct mvs_info *mvi, int bar, int bar_ex)
 
 	res_start = pci_resource_start(pdev, bar);
 	res_len = pci_resource_len(pdev, bar);
-	if (!res_start || !res_len)
+	if (!res_start || !res_len) {
+		iounmap(mvi->regs_ex);
+		mvi->regs_ex = NULL;
 		goto err_out;
+	}
 
 	res_flag = pci_resource_flags(pdev, bar);
 	if (res_flag & IORESOURCE_CACHEABLE)