ARM: dts: dra7-evm: add pcf8575 gpio expander (i2c1 addr 20)

This patch adds DT definition for CF8575 GPIO pcf_lcd: gpio@20
expander which is connected to i2c bus 1 and has slave address 0x20.
It allows to control:
- tc_lcd gpios, pins p0-p3
- user leds, pins p4-p7
- control LCD panel power, p15

PCF8575 GPIO pcf_lcd: gpio@20 expander supports interrupt controller
functionality and its INT line is connected to dra7 GPIO6.11 pin.

Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/dra7-evm.dts

@@ -479,6 +479,17 @@
 		};
 	};
 
+	pcf_lcd: gpio@20 {
+		compatible = "nxp,pcf8575";
+		reg = <0x20>;
+		gpio-controller;
+		#gpio-cells = <2>;
+		interrupt-parent = <&gpio6>;
+		interrupts = <11 IRQ_TYPE_EDGE_FALLING>;
+		interrupt-controller;
+		#interrupt-cells = <2>;
+	};
+
 	pcf_gpio_21: gpio@21 {
 		compatible = "ti,pcf8575";
 		reg = <0x21>;