boards: Convert stm32l476g_disco to HWM v2

Port the board to HWMv2.

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

boards/boards_legacy/arm/stm32l476g_disco/Kconfig.board

@@ -1,8 +0,0 @@
-# STM32L476G Discovery board configuration
-
-# Copyright (c) 2017 Arthur Sfez
-# SPDX-License-Identifier: Apache-2.0
-
-config BOARD_STM32L476G_DISCO
-	bool "STM32L476G Discovery Development Board"
-	depends on SOC_STM32L476XX

boards/boards_legacy/arm/stm32l476g_disco/Kconfig.defconfig

@@ -1,11 +0,0 @@
-# STM32L476G DISCOVERY board configuration
-
-# Copyright (c) 2017 Arthur Sfez
-# SPDX-License-Identifier: Apache-2.0
-
-if BOARD_STM32L476G_DISCO
-
-config BOARD
-	default "stm32l476g_disco"
-
-endif # BOARD_STM32L476G_DISCO

boards/st/stm32l476g_disco/Kconfig.stm32l476g_disco

@@ -0,0 +1,5 @@
+# Copyright (c) 2017 Arthur Sfez
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_STM32L476G_DISCO
+	select SOC_STM32L476XX

boards/st/stm32l476g_disco/board.yml

@@ -0,0 +1,5 @@
+board:
+  name: stm32l476g_disco
+  vendor: st
+  socs:
+    - name: stm32l476xx

boards/st/stm32l476g_disco/doc/index.rst

@@ -126,7 +126,7 @@ Other hardware features are not yet supported on this Zephyr port.
 
 The default configuration can be found in the defconfig file:
 
-	``boards/arm/stm32l476g_disco/stm32l476g_disco_defconfig``
+	``boards/st/stm32l476g_disco/stm32l476g_disco_defconfig``
 
 
 Connections and IOs

boards/st/stm32l476g_disco/stm32l476g_disco_defconfig

@@ -1,8 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
 
-CONFIG_SOC_SERIES_STM32L4X=y
-CONFIG_SOC_STM32L476XX=y
-
 # Enable MPU
 CONFIG_ARM_MPU=y