boards: Convert stm32f3_seco_d23 to HWM v2

Port the board to HWMv2.

Signed-off-by: Abderrahmane Jarmouni <abderrahmane.jarmouni-ext@st.com>

boards/boards_legacy/arm/stm32f3_seco_d23/Kconfig.board

@@ -1,8 +0,0 @@
-# SECO SBC-3.5-PX30 board configuration
-
-# Copyright (c) 2022, SECO Spa
-# SPDX-License-Identifier: Apache-2.0
-
-config BOARD_STM32F3_SECO_D23
-	bool "SECO SBC-3.5-PX30 (STM32F302VC) Board"
-	depends on SOC_STM32F302XC

boards/boards_legacy/arm/stm32f3_seco_d23/Kconfig.defconfig

@@ -1,11 +0,0 @@
-# SECO SBC-3.5-PX30 board configuration
-
-# Copyright (c) 2022, SECO Spa
-# SPDX-License-Identifier: Apache-2.0
-
-if BOARD_STM32F3_SECO_D23
-
-config BOARD
-	default "stm32f3_seco_d23"
-
-endif # BOARD_STM32F3_SECO_D23

boards/seco/stm32f3_seco_d23/Kconfig.stm32f3_seco_d23

@@ -0,0 +1,5 @@
+# Copyright (c) 2022, SECO Spa
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_STM32F3_SECO_D23
+	select SOC_STM32F302XC

boards/seco/stm32f3_seco_d23/board.yml

@@ -0,0 +1,5 @@
+board:
+  name: stm32f3_seco_d23
+  vendor: seco
+  socs:
+    - name: stm32f302xc

boards/seco/stm32f3_seco_d23/stm32f3_seco_d23_defconfig

@@ -3,9 +3,6 @@
 #
 # Copyright (c) 2022, SECO Spa
 
-CONFIG_SOC_SERIES_STM32F3X=y
-CONFIG_SOC_STM32F302XC=y
-
 # Enable MPU
 CONFIG_ARM_MPU=y