mpc86xx: Fix implicit declaration of functions 'init_laws' and 'disable_law'

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
diff --git a/cpu/mpc86xx/cpu_init.c b/cpu/mpc86xx/cpu_init.c
index ab5906d..0efd855 100644
--- a/cpu/mpc86xx/cpu_init.c
+++ b/cpu/mpc86xx/cpu_init.c
@@ -28,6 +28,7 @@
 
 #include <common.h>
 #include <mpc86xx.h>
+#include <asm/fsl_law.h>
 
 DECLARE_GLOBAL_DATA_PTR;