net: cirrus: use u8 for addr to calm down sparse

ep93xx_eth.c:805:40: sparse: sparse: incorrect type in argument 2
(different address spaces)
ep93xx_eth.c:805:40: sparse: expected unsigned char const [usertype] *addr
ep93xx_eth.c:805:40: sparse: got void [noderef] __iomem *

Reported-by: kernel test robot <[e-mail]>
Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/
Fixes: 858555bb5598 ("net: cirrus: add DT support for Cirrus EP93xx")
Signed-off-by: Nikita Shubin <[e-mail]>
Acked-by: Alexander Sverdlin <[e-mail]>
Signed-off-by: Arnd Bergmann <[e-mail]>

drivers/net/ethernet/cirrus/ep93xx_eth.c

···
 	struct resource *mem;
 	void __iomem *base_addr;
 	struct device_node *np;
+	u8 addr[ETH_ALEN];
 	u32 phy_id;
 	int irq;
 	int err;
···
 		goto err_out;
 	}
 
-	eth_hw_addr_set(dev, base_addr + 0x50);
+	memcpy_fromio(addr, base_addr + 0x50, ETH_ALEN);
+	eth_hw_addr_set(dev, addr);
 	dev->ethtool_ops = &ep93xx_ethtool_ops;
 	dev->netdev_ops = &ep93xx_netdev_ops;
 	dev->features |= NETIF_F_SG | NETIF_F_HW_CSUM;