Merge branch 'stmmac-100GB-Enterprise-MAC-support'

Merge branch 'stmmac-100GB-Enterprise-MAC-support'

Jose Abreu says:

====================
net: stmmac: 100GB Enterprise MAC support

Adds the support for Enterprise MAC IP version which allows operating
speeds up to 100GB.

Patch 1/4, adds the support in XPCS for XLGMII interface that is used in
this kind of Enterprise MAC IPs.

Patch 2/4, adds the XLGMII interface support in stmmac.

Patch 3/4, adds the HW specific support for Enterprise MAC.

We end in patch 4/4, by updating stmmac documentation to mention the
support for this new IP version.
====================

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