octeon_ep: Add missing check for ioremap

Add check for ioremap() and return the error if it fails in order to
guarantee the success of ioremap().

Fixes: 862cd65 ("octeon_ep: Add driver framework and device initialization")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Link: https://lore.kernel.org/r/20230615033400.2971-1-jiasheng@iscas.ac.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: JiangJias

drivers/net/ethernet/marvell/octeon_ep/octep_main.c

@@ -981,6 +981,9 @@ int octep_device_setup(struct octep_device *oct)
 		oct->mmio[i].hw_addr =
 			ioremap(pci_resource_start(oct->pdev, i * 2),
 				pci_resource_len(oct->pdev, i * 2));
+		if (!oct->mmio[i].hw_addr)
+			goto unmap_prev;
+
 		oct->mmio[i].mapped = 1;
 	}
 
@@ -1015,7 +1018,9 @@ int octep_device_setup(struct octep_device *oct)
 	return 0;
 
 unsupported_dev:
-	for (i = 0; i < OCTEP_MMIO_REGIONS; i++)
+	i = OCTEP_MMIO_REGIONS;
+unmap_prev:
+	while (i--)
 		iounmap(oct->mmio[i].hw_addr);
 
 	kfree(oct->conf);