include: Move snprintf to stdio.h

Move snprintf to stdio.h since it is needed by exteranl libraries.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/drivers/cpu/mpc83xx_cpu.c b/drivers/cpu/mpc83xx_cpu.c
index 9a7b5fd..127d3c3 100644
--- a/drivers/cpu/mpc83xx_cpu.c
+++ b/drivers/cpu/mpc83xx_cpu.c
@@ -9,7 +9,7 @@
 #include <cpu.h>
 #include <dm.h>
 #include <log.h>
-#include <vsprintf.h>
+#include <stdio.h>
 #include <linux/bitops.h>
 
 #include "mpc83xx_cpu.h"