Draft: New ethernet driver (stmmac) for Kernel 4.14

Hello,

I would like to submit a merge request for the original code of the stmmac device driver. This merge request includes the untouched, unmodified version of the stmmac device driver code.

The purpose of this merge request is to provide a baseline and ensure that any subsequent modifications or enhancements can be properly tracked and reviewed against the original code.

Please review and consider merging this request. Thank you.