[media] cec: don't zero reply and timeout on error

There is really no reason to zero the reply and timeout fields if an
error occurs. This is a left-over from earlier versions where that
was used to signal errors, but this is now handled by the rx/tx_status
fields.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>