media: tc358743: remove an unneeded condition

We can remove the check for if "state->cec_adap" is NULL.  The
cec_allocate_adapter() function never returns NULL and also we verified
that "state->cec_adap" is an error pointer.

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