media: adv7180: fix frame interval in progressive mode

media: adv7180: fix frame interval in progressive mode

The ADV7280-M may internally convert interlaced video input to
progressive video. If this mode is enabled, the ADV7280-M delivers
progressive video frames at the field rate of 50 fields per second (PAL)
or 60 fields per second (NTSC).

Fix the reported frame interval if progressive video is enabled.

Signed-off-by: Thorsten Schmelzer <tschmelzer@topcon.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>