ARM: dts: stm32: Fix DTC warnings for stm32mp157

Fix DTC warnings for stm32mp157:

Warning (unit_address_vs_reg): /soc/pin-controller: node has a reg or ranges property, but no unit name
Warning (unit_address_vs_reg): /soc/pin-controller/uart4@0: node has a unit name, but no reg property
Warning (unit_address_vs_reg): /soc/pin-controller-z: node has a reg or ranges property, but no unit name
Warning (unit_address_vs_reg): /memory: node has a reg or ranges property, but no unit name
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp157-pinctrl.dtsi

@@ -7,7 +7,7 @@
 
 / {
 	soc {
-		pinctrl: pin-controller {
+		pinctrl: pin-controller@50002000 {
 			#address-cells = <1>;
 			#size-cells = <1>;
 			compatible = "st,stm32mp157-pinctrl";
@@ -257,7 +257,7 @@ pins2 {
 				};
 			};
 
-			uart4_pins_a: uart4@0 {
+			uart4_pins_a: uart4-0 {
 				pins1 {
 					pinmux = <STM32_PINMUX('G', 11, AF6)>; /* UART4_TX */
 					bias-disable;
@@ -271,7 +271,7 @@ pins2 {
 			};
 		};
 
-		pinctrl_z: pin-controller-z {
+		pinctrl_z: pin-controller-z@54004000 {
 			#address-cells = <1>;
 			#size-cells = <1>;
 			compatible = "st,stm32mp157-z-pinctrl";

arch/arm/boot/dts/stm32mp157c-ed1.dts

@@ -16,7 +16,7 @@ chosen {
 		stdout-path = "serial0:115200n8";
 	};
 
-	memory {
+	memory@c0000000 {
 		reg = <0xC0000000 0x40000000>;
 	};