enic: Fix sparse warning in vnic_devcmd_init().

>> drivers/net/ethernet/cisco/enic/vnic_dev.c:1095:13: sparse: incorrect type in assignment (different address spaces)
   drivers/net/ethernet/cisco/enic/vnic_dev.c:1095:13:    expected void *res
   drivers/net/ethernet/cisco/enic/vnic_dev.c:1095:13:    got void [noderef] <asn:2>*

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cisco/enic/vnic_dev.c

@@ -1089,8 +1089,8 @@ EXPORT_SYMBOL(vnic_dev_get_pdev);
 
 int vnic_devcmd_init(struct vnic_dev *vdev)
 {
+	void __iomem *res;
 	int err;
-	void *res;
 
 	res = vnic_dev_get_res(vdev, RES_TYPE_DEVCMD2, 0);
 	if (res) {