Merge branch 'ptp-Add-adjust-phase-to-support-phase-offset'

Merge branch 'ptp-Add-adjust-phase-to-support-phase-offset'

Vincent Cheng says:

====================
ptp: Add adjust phase to support phase offset.

This series adds adjust phase to the PTP Hardware Clock device interface.

Some PTP hardware clocks have a write phase mode that has
a built-in hardware filtering capability.  The write phase mode
utilizes a phase offset control word instead of a frequency offset
control word.  Add adjust phase function to take advantage of this
capability.

Changes since v1:
- As suggested by Richard Cochran:
  1. ops->adjphase is new so need to check for non-null function pointer.
  2. Kernel coding style uses lower_case_underscores.
  3. Use existing PTP clock API for delayed worker.
====================

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