expanding on ethernet

expanded ethernet mac/phy, more configurability. replaced ethernet.o by the ethernet/ mac/phy files in f1/Makefile.
it's possibly (probably) academic, but there's probably no reason for this to be anything other than just "int" (in certain cases, requiring a smaller type like this will generate bigger code) See http://false.ekta.is/2012/07/code-size-changes-with-int-on-8bit-and-32bit-platforms/ for some anecdotes.