changing dt core

The latest version of duckietown/dt-core:daffy-arm32v7 image (for RaspberryPi) matches to a commit 330c20e9f5fae3f3b7978dbed354cb831f81e825 on a branch daffy here: https://github.com/duckietown/dt-core/tree/daffy

So, git reset --hard 330c20e9 and you can change code from dt-core on the fly like dts devel run -M -s -f -H autobotXX --

Do not try to rebuild dt-core.

¯\(ツ)/¯