[media] cec-adap: prevent write to out-of-bounds array index

CEC_MSG_REPORT_PHYSICAL_ADDR can theoretically be received from
an unregistered device, but in that case the code should not attempt
to write the received physical address to the phys_addrs array.

That would be pointless since there can be multiple unregistered
devices that report a physical address. We just ignore those.

While at it, improve the dprintk since it would attempt to read
from that array as well with the same out-of-bounds problem.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>