[media] cec: ignore messages when log_addr_mask == 0

[media] cec: ignore messages when log_addr_mask == 0

Most CEC adapters will still receive broadcast messages, even if no logical
addresses are claimed. But those messages should only be passed on for
monitoring purposes, but not for processing by either kernel or userspace
if userspace didn't call CEC_ADAP_S_LOG_ADDRS first.

So if adap->log_addrs.log_addr_mask is 0, then just return before passing
the received message on to the processing code.

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