media: rcar-csi2: Propagate the FLD signal for NTSC and PAL

Depending on which video standard is used the driver needs to setup the
hardware to correctly handle fields. If stream is identified as NTSC
or PAL setup field detection and propagate the field detection signal.

Later versions of the datasheet have been updated to make it clear
that FLD register should be set to 0 when dealing with non-interlaced
field formats.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>