media: cec: cec-adap: always cancel work in cec_transmit_msg_fh

Do not check for !data->completed, just always call
cancel_delayed_work_sync(). This fixes a small race condition.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reported-by: Yang, Chenyuan <cy54@illinois.edu>
Closes: https://lore.kernel.org/linux-media/PH7PR11MB57688E64ADE4FE82E658D86DA09EA@PH7PR11MB5768.namprd11.prod.outlook.com/
Fixes: 490d84f6

 ("media: cec: forgot to cancel delayed work")
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>