arch/powerpc/cpu/mpc8260/ether_scc.c: Fix compile warning

Fix this:
ether_scc.c: In function 'mpc82xx_scc_enet_initialize':
ether_scc.c:377:14: warning: assignment from incompatible pointer type

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>

arch/powerpc/cpu/mpc8260/ether_scc.c

@@ -105,7 +105,7 @@ typedef volatile struct CommonBufferDescriptor {
 static RTXBD *rtx;
 
 
-static int sec_send(struct eth_device *dev, volatile void *packet, int length)
+static int sec_send(struct eth_device *dev, void *packet, int length)
 {
     int i;
     int result = 0;