boards: Convert nucleo_f303re to HWM v2

Port the board to HWMv2.

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

boards/boards_legacy/arm/nucleo_f303re/Kconfig.board

@@ -1,8 +0,0 @@
-# NUCLEO-64 F303RE board configuration
-
-# Copyright (c) 2020 Paul M. Bendixen
-# SPDX-License-Identifier: Apache-2.0
-
-config BOARD_NUCLEO_F303RE
-	bool "NUCLEO-64 F303RE Development Board"
-	depends on SOC_STM32F303XE

boards/boards_legacy/arm/nucleo_f303re/Kconfig.defconfig

@@ -1,11 +0,0 @@
-# NUCLEO-64 F302R8 board configuration
-
-# Copyright (c) 2020 Paul M. Bendixen
-# SPDX-License-Identifier: Apache-2.0
-
-if BOARD_NUCLEO_F303RE
-
-config BOARD
-	default "nucleo_f303re"
-
-endif # BOARD_NUCLEO_F303RE

boards/st/nucleo_f303re/Kconfig.nucleo_f303re

@@ -0,0 +1,5 @@
+# Copyright (c) 2020 Paul M. Bendixen
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_NUCLEO_F303RE
+	select SOC_STM32F303XE

boards/st/nucleo_f303re/board.yml

@@ -0,0 +1,5 @@
+board:
+  name: nucleo_f303re
+  vendor: st
+  socs:
+    - name: stm32f303xe

boards/st/nucleo_f303re/nucleo_f303re_defconfig

@@ -1,8 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
 
-CONFIG_SOC_SERIES_STM32F3X=y
-CONFIG_SOC_STM32F303XE=y
-
 CONFIG_SERIAL=y
 
 # Enable MPU