[media] adv7604: Enable HDMI_MODE interrupt

Some sources are initially detected as DVI, and change to HDMI later.
This must be detected to set the right RGB quantization range.

Signed-off-by: Mats Randgaard <matrandg@cisco.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>