rockchip: clk: rk3399: update driver for spl

Add ddr clock setting, add rockchip_get_pmucru API,
and enable of-platdata support.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Added rockchip tag and fix pmuclk_init() build warning:
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/include/asm/arch-rockchip/clock.h b/arch/arm/include/asm/arch-rockchip/clock.h
index 804c77b..6f7e755 100644
--- a/arch/arm/include/asm/arch-rockchip/clock.h
+++ b/arch/arm/include/asm/arch-rockchip/clock.h
@@ -63,6 +63,13 @@
  */
 void *rockchip_get_cru(void);
 
+/**
+ * rockchip_get_pmucru() - get a pointer to the clock/reset unit registers
+ *
+ * @return pointer to registers, or -ve error on error
+ */
+void *rockchip_get_pmucru(void);
+
 struct rk3288_cru;
 struct rk3288_grf;