ARM: dts: stm32: add pull-up to USART3 and UART7 RX pins on STM32MP15 DKx boards

Add pull-up to USART3 and UART7 RX pins to allow loop tests between USART3
and UART7 on stm32mp15 DKx boards.
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

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

@@ -1816,7 +1816,7 @@ pins1 {
 		};
 		pins2 {
 			pinmux = <STM32_PINMUX('E', 7, AF7)>; /* UART7_RX */
-			bias-disable;
+			bias-pull-up;
 		};
 	};
 
@@ -1826,7 +1826,7 @@ pins1 {
 		};
 		pins2 {
 			pinmux = <STM32_PINMUX('E', 7, AF7)>; /* UART7_RX */
-			bias-disable;
+			bias-pull-up;
 		};
 	};
 
@@ -1971,7 +1971,7 @@ pins1 {
 		pins2 {
 			pinmux = <STM32_PINMUX('B', 12, AF8)>, /* USART3_RX */
 				 <STM32_PINMUX('I', 10, AF8)>; /* USART3_CTS_NSS */
-			bias-disable;
+			bias-pull-up;
 		};
 	};
 
@@ -1988,7 +1988,7 @@ pins2 {
 		};
 		pins3 {
 			pinmux = <STM32_PINMUX('B', 12, AF8)>; /* USART3_RX */
-			bias-disable;
+			bias-pull-up;
 		};
 	};
 
@@ -2012,7 +2012,7 @@ pins1 {
 		pins2 {
 			pinmux = <STM32_PINMUX('B', 12, AF8)>, /* USART3_RX */
 				 <STM32_PINMUX('B', 13, AF7)>; /* USART3_CTS_NSS */
-			bias-disable;
+			bias-pull-up;
 		};
 	};
 
@@ -2029,7 +2029,7 @@ pins2 {
 		};
 		pins3 {
 			pinmux = <STM32_PINMUX('B', 12, AF8)>; /* USART3_RX */
-			bias-disable;
+			bias-pull-up;
 		};
 	};