wifi: iwlwifi: mld: inform trans on init failure

wifi: iwlwifi: mld: inform trans on init failure

If starting the op mode failed, the opmode memory is being freed,
so trans->op_mode needs to be NULLified. Otherwise, trans will access
already freed memory.
Call iwl_trans_op_mode_leave in that case.

Fixes: d1e879ec600f ("wifi: iwlwifi: add iwlmld sub-driver")
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250420095642.3331d1686556.Ifaf15bdd8ef8c59e04effbd2e7aa0034b30eeacb@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>