ptp: netc: add NETC V4 Timer PTP driver support

NETC V4 Timer provides current time with nanosecond resolution, precise
periodic pulse, pulse on timeout (alarm), and time capture on external
pulse support. And it supports time synchronization as required for
IEEE 1588 and IEEE 802.1AS-2020.

Inside NETC, ENETC can capture the timestamp of the sent/received packet
through the PHC provided by the Timer and record it on the Tx/Rx BD. And
through the relevant PHC interfaces provided by the driver, the enetc V4
driver can support PTP time synchronization.

In addition, NETC V4 Timer is similar to the QorIQ 1588 timer, but it is
not exactly the same. The current ptp-qoriq driver is not compatible with
NETC V4 Timer, most of the code cannot be reused, see below reasons.

1. The architecture of ptp-qoriq driver makes the register offset fixed,
however, the offsets of all the high registers and low registers of V4
are swapped, and V4 also adds some new registers. so extending ptp-qoriq
to make it compatible with V4 Timer is tantamount to completely rewriting
ptp-qoriq driver.

2. The usage of some functions is somewhat different from QorIQ timer,
such as the setting of TCLK_PERIOD and TMR_ADD, the logic of configuring
PPS, etc., so making the driver compatible with V4 Timer will undoubtedly
increase the complexity of the code and reduce readability.

3. QorIQ is an expired brand. It is difficult for us to verify whether
it works stably on the QorIQ platforms if we refactor the driver, and
this will make maintenance difficult, so refactoring the driver obviously
does not bring any benefits.

Therefore, add this new driver for NETC V4 Timer. Note that the missing
features like PEROUT, PPS and EXTTS will be added in subsequent patches.

Signed-off-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20250829050615.1247468-5-wei.fang@nxp.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>