ppc: Fix warning in TSEC Ethernet driver

Fixes:
tsec.c: In function 'tsec_initialize':
tsec.c:638:12: warning: assignment from incompatible pointer type

Tested on MPC8313e-RDB

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

drivers/net/tsec.c

@@ -44,8 +44,7 @@ static RTXBD rtx __attribute__ ((aligned(8)));
 #error "rtx must be 64-bit aligned"
 #endif
 
-static int tsec_send(struct eth_device *dev,
-	volatile void *packet, int length);
+static int tsec_send(struct eth_device *dev, void *packet, int length);
 
 /* Default initializations for TSEC controllers. */
 
@@ -377,7 +376,7 @@ static void startup_tsec(struct eth_device *dev)
  * do the same.	 Presumably, this would be zero if there were no
  * errors
  */
-static int tsec_send(struct eth_device *dev, volatile void *packet, int length)
+static int tsec_send(struct eth_device *dev, void *packet, int length)
 {
 	int i;
 	int result = 0;