samples: protocol_serialization: fix uart hw flow dtc

Commit fixes uart dtc overlays to have working
hardware flow control.

Signed-off-by: Aleksandr Khromykh <[email protected]>

Author: alxelax

samples/nrf_rpc/protocols_serialization/client/boards/nrf54l15dk_nrf54l15_cpuapp.overlay

@@ -13,12 +13,9 @@
 	uart21_default: uart21_default {
 		group1 {
 			psels = <NRF_PSEL(UART_TX, 1, 11)>,
-				<NRF_PSEL(UART_RTS, 1, 12)>;
-		};
-		group2 {
-			psels = <NRF_PSEL(UART_RX, 1, 10)>,
+				<NRF_PSEL(UART_RX, 1, 10)>,
+				<NRF_PSEL(UART_RTS, 1, 12)>,
 				<NRF_PSEL(UART_CTS, 1, 13)>;
-			bias-pull-up;
 		};
 	};
 
@@ -40,6 +37,7 @@
 	pinctrl-0 = <&uart21_default>;
 	pinctrl-1 = <&uart21_sleep>;
 	pinctrl-names = "default", "sleep";
+	hw-flow-control;
 };
 
 /* restore full RRAM and SRAM space - by default some parts are dedicated to FLRP */

samples/nrf_rpc/protocols_serialization/server/boards/nrf54l15dk_nrf54l15_cpuapp.overlay

@@ -13,12 +13,9 @@
 	uart21_default: uart21_default {
 		group1 {
 			psels = <NRF_PSEL(UART_TX, 1, 11)>,
-				<NRF_PSEL(UART_RTS, 1, 12)>;
-		};
-		group2 {
-			psels = <NRF_PSEL(UART_RX, 1, 10)>,
+				<NRF_PSEL(UART_RX, 1, 10)>,
+				<NRF_PSEL(UART_RTS, 1, 12)>,
 				<NRF_PSEL(UART_CTS, 1, 13)>;
-			bias-pull-up;
 		};
 	};
 
@@ -40,6 +37,7 @@
 	pinctrl-0 = <&uart21_default>;
 	pinctrl-1 = <&uart21_sleep>;
 	pinctrl-names = "default", "sleep";
+	hw-flow-control;
 };
 
 /* restore full RRAM and SRAM space - by default some parts are dedicated to FLRP */