Merge branch 'axienet-clock-additions'

Robert Hancock says:

====================
axienet clock additions

Add support to the axienet driver for controlling all of the clocks that
the logic core may utilize.

Changed since v3:
-Added Acked-by to patch 1
-Now applies to net-next tree after earlier patches merged in - code
unchanged from v3

Changed since v2:
-Additional clock description clarification

Changed since v1:
-Clarified clock usages in documentation and code comments
====================

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