rk3288: add arch_cpu_init for rk3288

We do some SoC level one time setting initialization in
arch_cpu_init.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>

arch/arm/mach-rockchip/rk3288/Makefile

@@ -5,5 +5,6 @@
 #
 
 obj-y += clk_rk3288.o
+obj-y += rk3288.o
 obj-y += sdram_rk3288.o
 obj-y += syscon_rk3288.o

arch/arm/mach-rockchip/rk3288/rk3288.c

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2016 Rockchip Electronics Co., Ltd
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+#include <asm/io.h>
+#include <asm/arch/hardware.h>
+
+#define GRF_SOC_CON2 0x24c
+
+int arch_cpu_init(void)
+{
+	/* We do some SoC one time setting here. */
+
+	/* Use rkpwm by default */
+	rk_setreg(GRF_SOC_CON2, 1 << 0);
+
+	return 0;
+}