Apparently, -Wa,mlist-devices is not needed anymore
Apparently, -Wa,mlist-devices is not needed anymore

It's downright rejected by avr-gcc 6.2, and I tested with avr-gcc 4.9.2 and 4.8.2 without this option and it still dumped the MCU names.

Fixes #18

jawher/xavr,jawher/xavr