rockchip: move ROCKCHIP_STIMER_BASE to Kconfig

Move ROCKCHIP_STIMER_BASE to Kconfig.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/mach-rockchip/rk3399/Kconfig b/arch/arm/mach-rockchip/rk3399/Kconfig
index 0833e08..c1f2513 100644
--- a/arch/arm/mach-rockchip/rk3399/Kconfig
+++ b/arch/arm/mach-rockchip/rk3399/Kconfig
@@ -125,6 +125,9 @@
 config ROCKCHIP_BOOT_MODE_REG
 	default 0xff320300
 
+config ROCKCHIP_STIMER_BASE
+	default 0xff8680a0
+
 config SYS_SOC
 	default "rk3399"