Merge branch 'DSA-Felix-PTP'

Yangbo Lu says:

====================
Support PTP clock and hardware timestamping for DSA Felix driver

This patch-set is to support PTP clock and hardware timestamping
for DSA Felix driver. Some functions in ocelot.c/ocelot_board.c
driver were reworked/exported, so that DSA Felix driver was able
to reuse them as much as possible.

On TX path, timestamping works on packet which requires timestamp.
The injection header will be configured accordingly, and skb clone
requires timestamp will be added into a list. The TX timestamp
is final handled in threaded interrupt handler when PTP timestamp
FIFO is ready.
On RX path, timestamping is always working. The RX timestamp could
be got from extraction header.
====================

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