media: rcar-vin: Add support for V4L2_FIELD_SEQ_{TB,BT}

The hardware does not support capturing the field types
V4L2_FIELD_SEQ_TB and V4L2_FIELD_SEQ_BT. To capture in these formats the
driver needs to adjust the offset of the capture buffer and capture
twice to each vb2 buffer.

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