net: Always align tx packets

Make sure that TX packets are always cache-aligned.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/net/arp.c b/net/arp.c
index 990b771..b8a7168 100644
--- a/net/arp.c
+++ b/net/arp.c
@@ -182,7 +182,8 @@
 		    (net_read_ip(&arp->ar_spa).s_addr & net_netmask.s_addr))
 			udelay(5000);
 #endif
-		net_send_packet((uchar *)et, eth_hdr_size + ARP_HDR_SIZE);
+		memcpy(net_tx_packet, et, eth_hdr_size + ARP_HDR_SIZE);
+		net_send_packet(net_tx_packet, eth_hdr_size + ARP_HDR_SIZE);
 		return;
 
 	case ARPOP_REPLY:		/* arp reply */