Add Artix7 support

[enjoy-digital]

• [X] Add PHY.
• [x] Finish/Debug TX startup fsm. (PHINIT not working)
• [x] Finish/Debug RX startup fsm. (ADD DRP Reconfig)
• [x] Verify/Debug OOB initialization.
• [x] Verify/Debug Link layer.

[enjoy-digital]

It would be interesting to do https://github.com/enjoy-digital/litesata/issues/19 and test it on Kintex7 before continuing Artix7.

[enjoy-digital]

Artix7 is now supported and reuses TX/RX Init from LiteICLink.