media: Revert "media: rcar-vin: enable field toggle after a set number of lines for Gen3"

The offending commit was an attempt to fix the issue of writing outside
the capture buffer for VIN Gen3. Unfortunately it only fixed the symptom
of the problem to such a degree I could no longer reproduce it. Revert
the offending commit before a proper fix can be added in a follow-up
patch.

This reverts commit 015060cb.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hansverk@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>