boards: Convert nucleo_f207zg to HWM v2

Port the board to HWMv2.

Signed-off-by: Francois Ramu <francois.ramu@st.com>

boards/boards_legacy/arm/nucleo_f207zg/Kconfig.board

@@ -1,8 +0,0 @@
-# NUCLEO-144 F207ZG board configuration
-
-# Copyright (c) 2018 qianfan Zhao
-# SPDX-License-Identifier: Apache-2.0
-
-config BOARD_NUCLEO_F207ZG
-	bool "NUCLEO-144 F207ZG Development Board"
-	depends on SOC_STM32F207XX

boards/st/nucleo_f207zg/Kconfig.defconfig

@@ -5,9 +5,6 @@
 
 if BOARD_NUCLEO_F207ZG
 
-config BOARD
-	default "nucleo_f207zg"
-
 if NETWORKING
 
 config NET_L2_ETHERNET

boards/st/nucleo_f207zg/Kconfig.nucleo_f207zg

@@ -0,0 +1,5 @@
+# Copyright (c) 2018 qianfan Zhao
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_NUCLEO_F207ZG
+	select SOC_STM32F207XX

boards/st/nucleo_f207zg/board.yml

@@ -0,0 +1,5 @@
+board:
+  name: nucleo_f207zg
+  vendor: st
+  socs:
+    - name: stm32f207xx

boards/st/nucleo_f207zg/nucleo_f207zg_defconfig

@@ -1,8 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
 
-CONFIG_SOC_SERIES_STM32F2X=y
-CONFIG_SOC_STM32F207XX=y
-
 CONFIG_SERIAL=y
 
 # Enable MPU