Fix various compiler warnings on ppc4xx builds (ELDK 4.0)

Patch by Stefan Roese, 18 Jan 2006
diff --git a/board/esd/cms700/cms700.c b/board/esd/cms700/cms700.c
index 649619d..e4cfe14 100644
--- a/board/esd/cms700/cms700.c
+++ b/board/esd/cms700/cms700.c
@@ -114,7 +114,7 @@
 
 int checkboard (void)
 {
-	unsigned char str[64];
+	char str[64];
 	int flashcnt;
 	int delay;
 	volatile unsigned char *led_reg = (unsigned char *)((ulong)CFG_PLD_BASE + 0x1000);