net: enetc: add ptp timer binding support for i.MX94

net: enetc: add ptp timer binding support for i.MX94

The i.MX94 has three PTP timers, and all standalone ENETCs can select
one of them to bind to as their PHC. The 'ptp-timer' property is used
to represent the PTP device of the Ethernet controller. So users can
add 'ptp-timer' to the ENETC node to specify the PTP timer. The driver
parses this property to bind the two hardware devices.

If the "ptp-timer" property is not present, the first timer of the PCIe
bus where the ENETC is located is used as the default bound PTP timer.

Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
Signed-off-by: Wei Fang <wei.fang@nxp.com>
Link: https://patch.msgid.link/20251029013900.407583-5-wei.fang@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>