ARM: dts: dra7-evm: add gpio leds support

dra7-evm has 4 user gpio leds connected to PCF8575 GPIO pcf_lcd:
gpio@20 expander pins [4,5,6,7], so add corresponding DT nodes.

Do not enable any triggers by default as not all of them are proved
to work on -RT.
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

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

@@ -99,6 +99,33 @@ simple-audio-card,codec {
 			clocks = <&atl_clkin2_ck>;
 		};
 	};
+
+	leds {
+		compatible = "gpio-leds";
+		led@0 {
+			label = "dra7:usr1";
+			gpios = <&pcf_lcd 4 GPIO_ACTIVE_LOW>;
+			default-state = "off";
+		};
+
+		led@1 {
+			label = "dra7:usr2";
+			gpios = <&pcf_lcd 5 GPIO_ACTIVE_LOW>;
+			default-state = "off";
+		};
+
+		led@2 {
+			label = "dra7:usr3";
+			gpios = <&pcf_lcd 6 GPIO_ACTIVE_LOW>;
+			default-state = "off";
+		};
+
+		led@3 {
+			label = "dra7:usr4";
+			gpios = <&pcf_lcd 7 GPIO_ACTIVE_LOW>;
+			default-state = "off";
+		};
+	};
 };
 
 &dra7_pmx_core {