staging: slicoss: Fix warning of prefer ether_addr_copy().

This patch fixes the following checkpatch.pl warnings:
WARNING: "Prefer ether_addr_copy() over memcpy() if the Ethernet
addresses are __aligned(2)" in file slicoss.c
Pahole shows that the addresses are aligned.
Signed-off-by: Dilek Uzulmez <dilekuzulmez@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/slicoss/slicoss.c

@@ -1788,7 +1788,7 @@ static int slic_mcast_add_list(struct adapter *adapter, char *address)
 	if (mcaddr == NULL)
 		return 1;
 
-	memcpy(mcaddr->address, address, ETH_ALEN);
+	ether_addr_copy(mcaddr->address, address);
 
 	mcaddr->next = adapter->mcastaddrs;
 	adapter->mcastaddrs = mcaddr;