Cleanup for GCC-4.x
diff --git a/cpu/ppc4xx/i2c.c b/cpu/ppc4xx/i2c.c
index 3a644a4..be94b57 100644
--- a/cpu/ppc4xx/i2c.c
+++ b/cpu/ppc4xx/i2c.c
@@ -428,7 +428,7 @@
  */
 uchar i2c_reg_read(uchar i2c_addr, uchar reg)
 {
-	char buf;
+	uchar buf;
 
 	i2c_read(i2c_addr, reg, 1, &buf, 1);