ARM: dts: stm32: fix uart7_pins_a comments in stm32mp15-pinctrl

Fix uart7_pins_a comments to indicate UART7 pins instead of UART4 pins.

Fixes: bf4b5f37 ("ARM: dts: stm32: Add missing pinctrl definitions for STM32MP157")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp15-pinctrl.dtsi

@@ -1632,15 +1632,15 @@ pins2 {
 
 	uart7_pins_a: uart7-0 {
 		pins1 {
-			pinmux = <STM32_PINMUX('E', 8, AF7)>; /* UART4_TX */
+			pinmux = <STM32_PINMUX('E', 8, AF7)>; /* UART7_TX */
 			bias-disable;
 			drive-push-pull;
 			slew-rate = <0>;
 		};
 		pins2 {
-			pinmux = <STM32_PINMUX('E', 7, AF7)>, /* UART4_RX */
-				 <STM32_PINMUX('E', 10, AF7)>, /* UART4_CTS */
-				 <STM32_PINMUX('E', 9, AF7)>; /* UART4_RTS */
+			pinmux = <STM32_PINMUX('E', 7, AF7)>, /* UART7_RX */
+				 <STM32_PINMUX('E', 10, AF7)>, /* UART7_CTS */
+				 <STM32_PINMUX('E', 9, AF7)>; /* UART7_RTS */
 			bias-disable;
 		};
 	};