Merge branch 'Fully-describe-the-waveform-for-PTP-periodic-output'

Vladimir Oltean says:

====================
Fully describe the waveform for PTP periodic output

While using the ancillary pin functionality of PTP hardware clocks to
synchronize multiple DSA switches on a board, a need arised to be able
to configure the duty cycle of the master of this PPS hierarchy.

Also, the PPS master is not able to emit PPS starting from arbitrary
absolute times, so a new flag is introduced to support such hardware
without making guesses.

With these patches, struct ptp_perout_request now basically describes a
general-purpose square wave.

Changes in v2:
Made sure this applies to net-next.
====================

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