wifi: iwlwifi: mvm: fix race condition in PTP removal

wifi: iwlwifi: mvm: fix race condition in PTP removal

iwl_mvm_ptp_remove() calls cancel_delayed_work_sync() only after
ptp_clock_unregister() and clearing ptp_data state (ptp_clock,
ptp_clock_info, last_gp2).

This creates a race where the delayed work iwl_mvm_ptp_work() can
execute between ptp_clock_unregister() and cancel_delayed_work_sync(),
observing partially cleared PTP state.

Move cancel_delayed_work_sync() before ptp_clock_unregister() to
ensure the delayed work is fully stopped before any PTP cleanup
begins.

Cc: stable@vger.kernel.org
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Signed-off-by: Junjie Cao <junjie.cao@intel.com>
Link: https://patch.msgid.link/20260212125035.1345718-1-junjie.cao@intel.com
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>