net: stmmac: dwmac-imx: enable MAC propagation delay correction for i.MX8MP

As the i.MX8MP supports reading MAC propagation delay and correcting the
Hardware timestamp counter for additional delays [1], enable the feature
for this SoC.

This reduces phase error of the PPS output from the PTP Hardware Clock
from approx 150ns to 100ns.

[1] i.MX8MP Reference Manual, rev.1 Section 11.7.2.5.3 "Timestamp
correction"

Signed-off-by: Johannes Zink <j.zink@pengutronix.de>
Link: https://lore.kernel.org/r/20230719-stmmac_correct_mac_delay-v3-2-61e63427735e@pengutronix.de


Signed-off-by: Jakub Kicinski <kuba@kernel.org>