[Ethernet] Add support for the ethernet module STM32Fxx7 and Micrel PHY

Add initial support for the etnernet module.

Tested on STM32F417 board, compatible with F407 board.
Peripheral same with little modifications as in F107 (will be tested).

Perhaps peripheral comaptible with LPC43xx ethernet peripheral.

Pull if You like, or comment if You like some modifications (like some other PHY's).

API is not implemeted for all features of the core, but it should be good start for use lwip stack.

The lwip stack needs some arch code (dependent on lwip141) and i don't know how to publish it correctly.