media: cros-ec-cec: Don't exit early in .remove() callback

Exiting early in remove without releasing all acquired resources yields
leaks. Note that e.g. memory allocated with devm_zalloc() is freed after
.remove() returns, even if the return code was negative.

While blocking_notifier_chain_unregister() won't fail and so the
change is somewhat cosmetic, platform driver's .remove callbacks are
about to be converted to return void. To prepare that, keep the error
message but don't return early.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>