dt-bindings: rockchip: vop: add gamma_table range

Change-Id: Iafbff319d33c9436963572e05911ccfe676a4852
Signed-off-by: Mark Yao <mark.yao@rock-chips.com>

Documentation/devicetree/bindings/display/rockchip/rockchip-vop.txt

@@ -15,6 +15,12 @@ Required properties:
 		"rockchip,rk322x-vop";
 		"rockchip,rk3328-vop";
 
+- reg: there are two register region can configure for the device:
+  - first region: (Required) Base address and size of the controllers
+  - second region: (Optinal) Address and length of the gamma table,
+                   take care of this register's length, driver would use
+                   register's length to decide gamma table size.
+
 - interrupts: should contain a list of all VOP IP block interrupts in the
 		 order: VSYNC, LCD_SYSTEM. The interrupt specifier
 		 format depends on the interrupt controller used.
@@ -43,7 +49,7 @@ Example:
 SoC specific DT entry:
 	vopb: vopb@ff930000 {
 		compatible = "rockchip,rk3288-vop";
-		reg = <0xff930000 0x19c>;
+		reg = <0xff930000 0x19c>, <0xff931000 0x1000>;
 		interrupts = <GIC_SPI 15 IRQ_TYPE_LEVEL_HIGH>;
 		clocks = <&cru ACLK_VOP0>, <&cru DCLK_VOP0>, <&cru HCLK_VOP0>;
 		clock-names = "aclk_vop", "dclk_vop", "hclk_vop";