ptp: ocp: Fix NULL dereference in Adva board SMA sysfs operations

ptp: ocp: Fix NULL dereference in Adva board SMA sysfs operations

On Adva boards, SMA sysfs store/get operations can call
__handle_signal_outputs() or __handle_signal_inputs() while the `irig`
and `dcf` pointers are uninitialized, leading to a NULL pointer
dereference in __handle_signal() and causing a kernel crash. Adva boards
don't use `irig` or `dcf` functionality, so add Adva-specific callbacks
`ptp_ocp_sma_adva_set_outputs()` and `ptp_ocp_sma_adva_set_inputs()` that
avoid invoking `irig` or `dcf` input/output routines.

Fixes: ef61f5528fca ("ptp: ocp: add Adva timecard support")
Signed-off-by: Sagi Maimon <maimon.sagi@gmail.com>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://patch.msgid.link/20250429073320.33277-1-maimon.sagi@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>