[media] adv7180: Add I2P support

Some of the devices supported by this driver have a interlaced-to-
progressive converter which can optionally be enabled. This patch adds
support for enabling and disabling the I2P converter on such devices.

I2P mode can be enabled by selecting V4L2_FIELD_NONE instead of
V4L2_FIELD_INTERLACED for the format.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Federico Vaga <federico.vaga@gmail.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>