samd: Ignore a maybe-uninitialized diagnostic in asf4
samd: Ignore a maybe-uninitialized diagnostic in asf4

I encountered this when changing optimization flags for debugging
purposes.  The diagnostic appears spurious and unrelated to what
I'm debugging.

adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython