dt-bindings: pinctrl: rockchip: Add pinctrl support for rk1808

Add pinctrl support for RK1808 SoCs.

Change-Id: I6f198904c3481b65a3e04c3b687bde7965268e09
Signed-off-by: Jianqun Xu <[email protected]>

Author: jayxurockchip

Documentation/devicetree/bindings/pinctrl/rockchip,pinctrl.txt

@@ -21,6 +21,7 @@ defined as gpio sub-nodes of the pinmux controller.
 Required properties for iomux controller:
   - compatible: should be
 		"rockchip,px30-pinctrl":    for Rockchip PX30
+		"rockchip,rk1808-pinctrl":  for Rockchip RK1808
 		"rockchip,rk2928-pinctrl":  for Rockchip RK2928
 		"rockchip,rk3066a-pinctrl": for Rockchip RK3066a
 		"rockchip,rk3066b-pinctrl": for Rockchip RK3066b