media: imx-csi: Double crop height for alternate fields at sink

If the incoming sink field type is alternate, the reset crop height
and crop height bounds must be set to twice the incoming height,
because in alternate field mode, upstream will report only the
lines for a single field, and the CSI captures the whole frame.

Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>