boards: Convert nucleo_g474re to HWM v2

Port the board to HWMv2.

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

boards/boards_legacy/arm/nucleo_g474re/Kconfig.board

@@ -1,8 +0,0 @@
-# STM32G474RE Nucleo board configuration
-
-# Copyright (c) 2019 STMicroelectronics.
-# SPDX-License-Identifier: Apache-2.0
-
-config BOARD_NUCLEO_G474RE
-	bool "Nucleo G474RE Development Board"
-	depends on SOC_STM32G474XX

boards/st/nucleo_g474re/Kconfig.defconfig

@@ -5,9 +5,6 @@
 
 if BOARD_NUCLEO_G474RE
 
-config BOARD
-	default "nucleo_g474re"
-
 config SPI_STM32_INTERRUPT
 	default y
 	depends on SPI

boards/st/nucleo_g474re/Kconfig.nucleo_g474re

@@ -0,0 +1,5 @@
+# Copyright (c) 2019 STMicroelectronics.
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_NUCLEO_G474RE
+	select SOC_STM32G474XX

boards/st/nucleo_g474re/board.yml

@@ -0,0 +1,5 @@
+board:
+  name: nucleo_g474re
+  vendor: st
+  socs:
+    - name: stm32g474xx

boards/st/nucleo_g474re/nucleo_g474re_defconfig

@@ -1,8 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
 
-CONFIG_SOC_SERIES_STM32G4X=y
-CONFIG_SOC_STM32G474XX=y
-
 # enable uart driver
 CONFIG_SERIAL=y