Cleanup for GCC-4.x
diff --git a/cpu/mpc8xx/spi.c b/cpu/mpc8xx/spi.c
index 9213d10..e318ed0 100644
--- a/cpu/mpc8xx/spi.c
+++ b/cpu/mpc8xx/spi.c
@@ -525,11 +525,11 @@
 
 	for (i = 0; i < TEST_NUM; i++) {
 		for (l = TEST_MIN_LENGTH; l <= TEST_MAX_LENGTH; l += 8) {
-			packet_fill (txbuf, l);
+			packet_fill ((char *)txbuf, l);
 
 			spi_xfer (l);
 
-			if (packet_check (rxbuf, l) < 0) {
+			if (packet_check ((char *)rxbuf, l) < 0) {
 				goto Done;
 			}
 		}