boards: Convert weact_stm32g431_core to HWM v2

Port the board to HWMv2.

Signed-off-by: Guillaume Gautier <guillaume.gautier-ext@st.com>

boards/boards_legacy/arm/weact_stm32g431_core/Kconfig.defconfig

@@ -1,12 +0,0 @@
-#
-# Copyright (c) 2023 Andreas Sandberg
-#
-# SPDX-License-Identifier: Apache-2.0
-#
-
-if BOARD_WEACT_STM32G431_CORE
-
-config BOARD
-	default "weact_stm32g431_core"
-
-endif

boards/weact/weact_stm32g431_core/Kconfig.weact_stm32g431_core

@@ -1,9 +1,5 @@
-#
 # Copyright (c) 2023 Andreas Sandberg
-#
 # SPDX-License-Identifier: Apache-2.0
-#
 
 config BOARD_WEACT_STM32G431_CORE
-	bool "WeAct Studio STM32G431 Core Board"
-	depends on SOC_STM32G431XX
+	select SOC_STM32G431XX

boards/weact/weact_stm32g431_core/board.yml

@@ -0,0 +1,5 @@
+board:
+  name: weact_stm32g431_core
+  vendor: weact
+  socs:
+    - name: stm32g431xx

boards/weact/weact_stm32g431_core/weact_stm32g431_core_defconfig

@@ -4,9 +4,6 @@
 # SPDX-License-Identifier: Apache-2.0
 #
 
-CONFIG_SOC_SERIES_STM32G4X=y
-CONFIG_SOC_STM32G431XX=y
-
 CONFIG_CLOCK_CONTROL=y
 CONFIG_PINCTRL=y