[media] em28xx: add support for EM28174 chip

EM28174 is very similar as already supported EM2874.
I am not sure what are differences, but it could be analog support.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>