[media] cec: fix wrong last_la determination

Due to an incorrect condition the last_la used for the initial attempt at
claiming a logical address could be wrong.

The last_la wasn't converted to a mask when ANDing with type2mask, so that
test was broken.

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