rockchip: rv1108: Enable grf as pre-reloc node

The grf node will be used before relocate, enable it in dts.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/dts/rv1108-u-boot.dtsi b/arch/arm/dts/rv1108-u-boot.dtsi
index 41ac054..6a2098b 100644
--- a/arch/arm/dts/rv1108-u-boot.dtsi
+++ b/arch/arm/dts/rv1108-u-boot.dtsi
@@ -4,3 +4,7 @@
  */
 
 #include "rockchip-u-boot.dtsi"
+
+&grf {
+	u-boot,dm-pre-reloc;
+};