rk3399: syscon: add support for pmugrf

pmugrf is a module like grf which contain some of the iomux registers
and other registers.

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

arch/arm/include/asm/arch-rockchip/clock.h

@@ -16,6 +16,7 @@ enum {
 	ROCKCHIP_SYSCON_GRF,
 	ROCKCHIP_SYSCON_SGRF,
 	ROCKCHIP_SYSCON_PMU,
+	ROCKCHIP_SYSCON_PMUGRF,
 };
 
 /* Standard Rockchip clock numbers */

arch/arm/mach-rockchip/rk3399/syscon_rk3399.c

@@ -11,6 +11,7 @@
 
 static const struct udevice_id rk3399_syscon_ids[] = {
 	{ .compatible = "rockchip,rk3399-grf", .data = ROCKCHIP_SYSCON_GRF },
+	{ .compatible = "rockchip,rk3399-pmugrf", .data = ROCKCHIP_SYSCON_PMUGRF },
 };
 
 U_BOOT_DRIVER(syscon_rk3399) = {