boards: Convert nucleo_l412rb_p to HWM v2

Port the board to HWMv2.

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

boards/boards_legacy/arm/nucleo_l412rb_p/Kconfig.board

@@ -1,8 +0,0 @@
-# STM32L412RB Nucleo board configuration
-
-# Copyright (c) 2021 Guðni Már Gilbert
-# SPDX-License-Identifier: Apache-2.0
-
-config BOARD_NUCLEO_L412RB_P
-	bool "Nucleo L412RB-P Development Board"
-	depends on SOC_STM32L412XX

boards/st/nucleo_l412rb_p/Kconfig.defconfig

@@ -5,9 +5,6 @@
 
 if BOARD_NUCLEO_L412RB_P
 
-config BOARD
-	default "nucleo_l412rb_p"
-
 config SPI_STM32_INTERRUPT
 	default y
 	depends on SPI

boards/st/nucleo_l412rb_p/Kconfig.nucleo_l412rb_p

@@ -0,0 +1,5 @@
+# Copyright (c) 2021 Guðni Már Gilbert
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_NUCLEO_L412RB_P
+	select SOC_STM32L412XX

boards/st/nucleo_l412rb_p/board.yml

@@ -0,0 +1,5 @@
+board:
+  name: nucleo_l412rb_p
+  vendor: st
+  socs:
+    - name: stm32l412xx

boards/st/nucleo_l412rb_p/doc/index.rst

@@ -161,7 +161,7 @@ The Zephyr ``nucleo_l412rb_p`` board configuration supports the following hardwa
 Other hardware features are not yet supported on this Zephyr port.
 
 The default configuration can be found in the defconfig file:
-``boards/arm/nucleo_l412rb_p/nucleo_l412rb_p_defconfig``
+``boards/st/nucleo_l412rb_p/nucleo_l412rb_p_defconfig``
 
 
 Connections and IOs

boards/st/nucleo_l412rb_p/nucleo_l412rb_p_defconfig

@@ -1,8 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
 
-CONFIG_SOC_SERIES_STM32L4X=y
-CONFIG_SOC_STM32L412XX=y
-
 # Enable MPU
 CONFIG_ARM_MPU=y