media: stih-cec: use CEC_CAP_DEFAULTS

Use the new CEC_CAP_DEFAULTS define in this driver.
This also adds the CEC_CAP_RC capability which was missing here
(and this is also the reason for this new define, to avoid missing
such capabilities).

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>