* Rockchip 4g modem device tree bindings

Required properties:
- compatible : "4g-modem-platdata"

Optional properties:
- 4G,vbat-gpio : 4g modem vbat gpio
- 4G,power-gpio : 4g modem power enable/disable gpio
- 4G,reset-gpio : 4g modem reset gpio

Example:

	4G-Modem {
		compatible="4g-modem-platdata";
		4G,vbat-gpio = <&gpio0 RK_PA4 GPIO_ACTIVE_HIGH>;
		4G,power-gpio = <&gpio0 RK_PC0 GPIO_ACTIVE_LOW>;
		4G,reset-gpio = <&gpio0 RK_PB7 GPIO_ACTIVE_LOW>;
	}