net: wwan: iosm: clean up unused struct members

Below members are unused.
- td_tag member defined in struct ipc_pipe.
- adb_finish_timer & params defined in struct iosm_mux.

Remove it to avoid unexpected usage.

Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/92ee483d79dfc871ed7408da8fec60b395ff3a9c.1683649868.git.m.chetan.kumar@linux.intel.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>