[bsp][wch]to clear the serial of ch32v20x

Author: kaidegit

bsp/wch/risc-v/Libraries/Kconfig

@@ -13,6 +13,15 @@ config SOC_RISCV_SERIES_CH32V2
     select SOC_RISCV_FAMILY_CH32
     select RT_USING_HW_ATOMIC
 
+config SOC_RISCV_SERIES_CH32V20x_D6
+    bool
+
+config SOC_RISCV_SERIES_CH32V20x_D8
+    bool
+
+config SOC_RISCV_SERIES_CH32V20x_D8W
+    bool
+
 config SOC_RISCV_SERIES_CH32V3
     bool
     select ARCH_RISCV

bsp/wch/risc-v/ch32v208w-r0/board/Kconfig

@@ -3,6 +3,7 @@ menu "Hardware Drivers Config"
 config SOC_CH32V208WBU6
     bool
     select SOC_RISCV_SERIES_CH32V2
+    select SOC_RISCV_SERIES_CH32V20x_D8W
     select RT_USING_COMPONENTS_INIT
     select RT_USING_USER_MAIN
     default y