[bsp][stm32] optimize flash driver config
@@ -57,6 +57,8 @@ src += ['drv_common.c']
path = [cwd]
path += [cwd + '/config']
+
+if GetDepend('BSP_USING_ON_CHIP_FLASH'):
path += [cwd + '/drv_flash']
group = DefineGroup('Drivers', src, depend = [''], CPPPATH = path)
