ptp_ocp: make ptp_ocp driver compatible with PTP_EXTTS_REQUEST2

ptp_ocp: make ptp_ocp driver compatible with PTP_EXTTS_REQUEST2

Originally ptp_ocp driver was not strictly checking flags for external
timestamper and was always activating rising edge timestamping as it's
the only supported mode. Recent changes to ptp made it incompatible with
PTP_EXTTS_REQUEST2 ioctl. Adjust ptp_clock_info to provide supported
mode and be compatible with new infra.

While at here remove explicit check of periodic output flags from the
driver and provide supported flags for ptp core to check.

Signed-off-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://patch.msgid.link/20250918131146.651468-1-vadim.fedorenko@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>