add gd32407v-start

bsp/gd32/README.md

+
+# GD32 BSP 说明
+
+GD32 系列 BSP 目前支持情况如下表所示：
+
+| **BSP 文件夹名称**       | **开发板名称**                 |
+|:------------------------- |:-------------------------- |
+| **F4 系列** |  |
+| [gd32407v-start](gd32407v-start) | 兆易创新 官方 GD32407V-START 开发板 |
+

bsp/gd32/gd32407v-start/SConstruct

@@ -47,11 +47,11 @@ Export('SDK_LIB')
 # prepare building environment
 objs = PrepareBuilding(env, RTT_ROOT, has_libcpu=False)
 
-stm32_library = 'GD32F4xx_HAL'
-rtconfig.BSP_LIBRARY_TYPE = stm32_library
+gd32_library = 'GD32F4xx_HAL'
+rtconfig.BSP_LIBRARY_TYPE = gd32_library
 
 # include libraries
-objs.extend(SConscript(os.path.join(libraries_path_prefix, stm32_library, 'SConscript')))
+objs.extend(SConscript(os.path.join(libraries_path_prefix, gd32_library, 'SConscript')))
 
 # include drivers
 objs.extend(SConscript(os.path.join(libraries_path_prefix, 'HAL_Drivers', 'SConscript')))