RE: [PATCH net v5 1/2] net: fec: Propagate PTP initialization errors

Change fec_ptp_init() to return an error code instead of silently
ignoring failures during PTP initialization.

The PPS IRQ is not required for the FEC/PTP functionality, so its
absence should not make the probe fail. However, an unavailable
optional IRQ should be distinguished from an actual error returned
during the IRQ lookup.

If a platform does not support the PPS IRQ, it can omit the IRQ from
its device tree and the optional lookup will return -ENXIO. Propagate
other errors from the IRQ lookup instead of silently ignoring them.
In particular, silently ignoring -EPROBE_DEFER can cause the driver to
continue probing instead of deferring as required.

Also propagate failures from devm_request_irq() and ptp_clock_register().

Update the function declaration in fec.h accordingly.

Found by manual code inspection.

Fixes: b86bcb299092 ("net: fec_ptp: Use platform_get_irq_xxx_optional() to
avoid error message")
Signed-off-by: bui duc phuc <redacted>

Reviewed-by: Wei Fang <wei.fang@nxp.com>