stm32mp1: add stusb1600 support for DK1 and DK2 board

The DK1 and DK2 boards use the USB Type-C controller STUSB1600.
This patch updates:
- the device tree to add the I2C node in the DT
- the board stm32mp1 to probe this I2C device and use this controller
  to check cable detection.
- the DWC2 driver to support a new dt property
  "u-boot,force-b-session-valid" which forces B session and
  device mode; it is a workaround because the VBUS sensing and
  ID detection isn't available with stusb1600.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Lukasz Majewski <lukma@denx.de>

arch/arm/dts/stm32mp157-pinctrl.dtsi

@@ -375,6 +375,13 @@
 				};
 			};
 
+			stusb1600_pins_a: stusb1600-0 {
+				pins {
+					pinmux = <STM32_PINMUX('I', 11, ANALOG)>;
+					bias-pull-up;
+				};
+			};
+
 			uart4_pins_a: uart4-0 {
 				pins1 {
 					pinmux = <STM32_PINMUX('G', 11, AF6)>; /* UART4_TX */

arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi

@@ -191,7 +191,7 @@
 };
 
 &usbotg_hs {
-	force-b-session-valid;
+	u-boot,force-b-session-valid;
 	hnp-srp-disable;
 };
 

arch/arm/dts/stm32mp157a-dk1.dts

@@ -67,6 +67,24 @@
 	/delete-property/dmas;
 	/delete-property/dma-names;
 
+	typec: stusb1600@28 {
+		compatible = "st,stusb1600";
+		reg = <0x28>;
+		interrupts = <11 IRQ_TYPE_EDGE_FALLING>;
+		interrupt-parent = <&gpioi>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&stusb1600_pins_a>;
+
+		status = "okay";
+
+		typec_con: connector {
+			compatible = "usb-c-connector";
+			label = "USB-C";
+			power-role = "sink";
+			power-opmode = "default";
+		};
+	};
+
 	pmic: stpmic@33 {
 		compatible = "st,stpmic1";
 		reg = <0x33>;