Merge branch 'support-external-snapshots-on-dwmac1000'

Merge branch 'support-external-snapshots-on-dwmac1000'

Maxime Chevallier says:

====================
Support external snapshots on dwmac1000

The main change since v3 is the move of the fifo flush wait in the
ptp_clock_info enable() function within the mutex that protects the ptp
registers. Thanks Jakub and Paolo for spotting this.

This series also aggregates Daniel's reviews, except for the patch 4
which was modified since then.

This series is another take on the previous work [1] done by
Alexis Lothoré, that fixes the support for external snapshots
timestamping in GMAC3-based devices.

Details on why this is needed are mentionned on the cover [2] from V1.

[1]: https://lore.kernel.org/netdev/20230616100409.164583-1-alexis.lothore@bootlin.com/
[2]: https://lore.kernel.org/netdev/20241029115419.1160201-1-maxime.chevallier@bootlin.com/

Link to V1: https://lore.kernel.org/netdev/20241029115419.1160201-1-maxime.chevallier@bootlin.com/
Link to V2: https://lore.kernel.org/netdev/20241104170251.2202270-1-maxime.chevallier@bootlin.com/
Link to V3: https://lore.kernel.org/netdev/20241106090331.56519-1-maxime.chevallier@bootlin.com/
====================

Link: https://patch.msgid.link/20241112170658.2388529-1-maxime.chevallier@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>