Merge pull request adafruit#4356 from jerryneedell/jerryn_blackpill_flash

 add GD25Q16C flash to BlackPill

Author: jepler

ports/stm/boards/stm32f411ce_blackpill_with_flash/mpconfigboard.mk

@@ -4,9 +4,9 @@ USB_PRODUCT = "stm32f411ce blackpill with flash"
 USB_MANUFACTURER = "Unknown"
 
 SPI_FLASH_FILESYSTEM = 1
-EXTERNAL_FLASH_DEVICE_COUNT = 2
+EXTERNAL_FLASH_DEVICE_COUNT = 3
 #See supervisor/shared/external_flash/devices.h for options
-EXTERNAL_FLASH_DEVICES = W25Q64FV,W25Q64JV_IQ
+EXTERNAL_FLASH_DEVICES = GD25Q16C,W25Q64FV,W25Q64JV_IQ
 LONGINT_IMPL = MPZ
 
 INTERNAL_FLASH_FILESYSTEM = 0