stm32f746: to switch on user LED1 & read user button

All discovery boards have one user button & one user LED. Here we are
just reading the button status & switching ON the user LED.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
cc: Christophe KERELLO <christophe.kerello@st.com>
diff --git a/arch/arm/dts/stm32f746-disco.dts b/arch/arm/dts/stm32f746-disco.dts
index f830aa9..8e4576b 100644
--- a/arch/arm/dts/stm32f746-disco.dts
+++ b/arch/arm/dts/stm32f746-disco.dts
@@ -78,6 +78,16 @@
 		gpio9 = &gpioj;
 		gpio10 = &gpiok;
 	};
+
+	led1 {
+		compatible = "st,led1";
+		led-gpio = <&gpioi 1 0>;
+	};
+
+	button1 {
+		compatible = "st,button1";
+		button-gpio = <&gpioi 11 0>;
+	};
 };
 
 &clk_hse {