Merge branch 'txgbe-link-modes'

Jiawen Wu says:

====================
support more link mode for TXGBE

There are three new interface mode support for Wangxun 10Gb NICs:
1000BASE-X, SGMII and XAUI.

Specific configurations are added to XPCS. And external PHY attaching
is added for copper NICs.

v2 -> v3:
- add device identifier read
- restrict pcs soft reset
- add firmware version warning

v1 -> v2:
- use the string "txgbe_pcs_mdio_bus" directly
- use dev_err() instead of pr_err()
- add device quirk flag
- add more macro definitions to explain PMA registers
- move txgbe_enable_sec_tx_path() to mac_finish()
- implement phylink for copper NICs
====================

Signed-off-by: David S. Miller <davem@davemloft.net>