boards: Convert nucleo_f446ze to HWM v2

Port the board to HWMv2.

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

boards/boards_legacy/arm/nucleo_f446ze/Kconfig.board

@@ -1,8 +0,0 @@
-# STM32F446ZE Nucleo board configuration
-
-# Copyright (c) 2021 Tom Owen
-# SPDX-License-Identifier: Apache-2.0
-
-config BOARD_NUCLEO_F446ZE
-	bool "Nucleo F446ZE Development Board"
-	depends on SOC_STM32F446XX

boards/st/nucleo_f446ze/Kconfig.defconfig

@@ -5,9 +5,6 @@
 
 if BOARD_NUCLEO_F446ZE
 
-config BOARD
-	default "nucleo_f446ze"
-
 config SPI_STM32_INTERRUPT
 	default y
 	depends on SPI

boards/st/nucleo_f446ze/Kconfig.nucleo_f446ze

@@ -0,0 +1,5 @@
+# Copyright (c) 2021 Tom Owen
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_NUCLEO_F446ZE
+	select SOC_STM32F446XX

boards/st/nucleo_f446ze/board.yml

@@ -0,0 +1,5 @@
+board:
+  name: nucleo_f446ze
+  vendor: st
+  socs:
+    - name: stm32f446xx

boards/st/nucleo_f446ze/nucleo_f446ze_defconfig

@@ -1,8 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
 
-CONFIG_SOC_SERIES_STM32F4X=y
-CONFIG_SOC_STM32F446XX=y
-
 # Enable MPU
 CONFIG_ARM_MPU=y