fix flash size for xiao_esp32c5.

Author: AZKKXL

boards.txt

@@ -36262,10 +36262,6 @@ XIAO_ESP32C5.menu.FlashFreq.40.build.flash_freq=40m
 
 XIAO_ESP32C5.menu.FlashSize.8M=8MB (64Mb)
 XIAO_ESP32C5.menu.FlashSize.8M.build.flash_size=8MB
-XIAO_ESP32C5.menu.FlashSize.4M=4MB (32Mb)
-XIAO_ESP32C5.menu.FlashSize.4M.build.flash_size=4MB
-XIAO_ESP32C5.menu.FlashSize.2M=2MB (16Mb)
-XIAO_ESP32C5.menu.FlashSize.2M.build.flash_size=2MB
 
 XIAO_ESP32C5.menu.UploadSpeed.921600=921600
 XIAO_ESP32C5.menu.UploadSpeed.921600.upload.speed=921600