The CX18_AUDIO_ENABLE register usually never reads back what was just written
under normal circumstances.  Perform better checking that a write went to the
register as expected with a specification of what bits to verify.
Signed-off-by: NAndy Walls <awalls@radix.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>