rename CFG_ macros to CONFIG_SYS

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
diff --git a/cpu/mpc512x/interrupts.c b/cpu/mpc512x/interrupts.c
index 8cc241c..ef7c773 100644
--- a/cpu/mpc512x/interrupts.c
+++ b/cpu/mpc512x/interrupts.c
@@ -37,7 +37,7 @@
 
 int interrupt_init_cpu (unsigned *decrementer_count)
 {
-	*decrementer_count = get_tbclk () / CFG_HZ;
+	*decrementer_count = get_tbclk () / CONFIG_SYS_HZ;
 
 	return 0;
 }