ptp: ocp: reject unsupported periodic output flags

The ptp_ocp_signal_from_perout() function supports PTP_PEROUT_DUTY_CYCLE
and PTP_PEROUT_PHASE. It does not support PTP_PEROUT_ONE_SHOT, but does not
reject a request with such an unsupported flag.

Add the appropriate check to ensure that unsupported requests are rejected
both for PTP_PEROUT_ONE_SHOT as well as any future flags.

Fixes: 1aa66a3a ("ptp: ocp: Program the signal generators via PTP_CLK_REQ_PEROUT")
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250312-jk-net-fixes-supported-extts-flags-v2-5-ea930ba82459@intel.com


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