sx933x cap touch sensor from semtech

It is a i2c slave device
two specific properties for driver init registers's value

a).CONFIG_INPUT_SX933x corresponding driver sx933x_sar.c,
sx933x is 5 channels driver.

Required properties:
 - Semtech,button-flag	:flag of used buttons,0~4 bits refers to button 0~4
 - Semtech,reg-num	:num of registers need to be set
 - Semtech,reg-init	:registers's val, format is <reg addr, reg val ...>

Example:

	sx933x@28 {
		compatible = "Semtech,sx933x";
		reg = <0x28>;
		interrupt-parent = <&tlmm>;
		interrupts = <75 0>;
		Semtech,nirq-gpio = <&tlmm 75 0x00>;
		cap_vdd-supply = <&pm660l_l8>;
		Semtech,reg-num = <12>;
		Semtech,button-flag = <0x07>; //used button 0~2
		Semtech,reg-init = <0x8020 0x3F00C0
			0x8024 0x44F
			0x8028 0x24928000
			0x802C 0x44F
			0x8030 0x24960000
			0x8034 0x44F
			0x8038 0x24B20000
			0x803C 0x44F
			0x8040 0x25920000
			0x8044 0x44F
			0x8048 0x2C920000
			0x4004 0x67 >;
	};
