net: dsa: bcm_sf2: fix unmapping registers in case of errors

In case we fail to ioremap() one of our registers, we would be leaking
existing mappings, unwind those accordingly on errors.

Fixes: 246d7f77 ("net: dsa: add Broadcom SF2 switch driver")
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/dsa/bcm_sf2.c

@@ -404,7 +404,8 @@ static int bcm_sf2_sw_setup(struct dsa_switch *ds)
 		*base = of_iomap(dn, i);
 		if (*base == NULL) {
 			pr_err("unable to find register: %s\n", reg_names[i]);
-			return -ENODEV;
+			ret = -ENOMEM;
+			goto out_unmap;
 		}
 		base++;
 	}
@@ -484,7 +485,8 @@ static int bcm_sf2_sw_setup(struct dsa_switch *ds)
 out_unmap:
 	base = &priv->core;
 	for (i = 0; i < BCM_SF2_REGS_NUM; i++) {
-		iounmap(*base);
+		if (*base)
+			iounmap(*base);
 		base++;
 	}
 	return ret;