media: ti-vpe: cal: set field always to V4L2_FIELD_NONE

cal_camerarx_sd_set_fmt() accepts any value for the format field, but
there should be no reason to have any other value accepted than
V4L2_FIELD_NONE. So set the field always to V4L2_FIELD_NONE.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>