updated to fastpin_arm_d51.h (#834)
updated to fastpin_arm_d51.h (#834)

Added pin defs for the Adafruit Metro M4 Airlift Lite
FastLED/FastLED,FastLED/FastLED,FastLED/FastLED,FastLED/FastLED,PaulStoffregen/FastLED,PaulStoffregen/FastLED,PaulStoffregen/FastLED