media: nxp: imx8-isi: fix v4l2-compliance test errors

Running the v4l2-compliance (1.27.0-5208, SHA: af114250d48d) on the m2m
device fails on the MMAP streaming tests, with the following messages:

fail: v4l2-test-buffers.cpp(240): g_field() == V4L2_FIELD_ANY
fail: v4l2-test-buffers.cpp(1508): buf.qbuf(node)

Apparently, the driver does not properly set the field member of
vb2_v4l2_buffer struct, returning the default V4L2_FIELD_ANY value which
is against the guidelines.

Fixes: cf21f32 ("media: nxp: Add i.MX8 ISI driver")
Signed-off-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20240924103304.124085-1-laurentiu.palcu@oss.nxp.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

Author: Laurentiu Palcu

drivers/media/platform/nxp/imx8-isi/imx8-isi-video.c

@@ -861,6 +861,7 @@ int mxc_isi_video_buffer_prepare(struct mxc_isi_dev *isi, struct vb2_buffer *vb2
 				 const struct mxc_isi_format_info *info,
 				 const struct v4l2_pix_format_mplane *pix)
 {
+	struct vb2_v4l2_buffer *v4l2_buf = to_vb2_v4l2_buffer(vb2);
 	unsigned int i;
 
 	for (i = 0; i < info->mem_planes; i++) {
@@ -875,6 +876,8 @@ int mxc_isi_video_buffer_prepare(struct mxc_isi_dev *isi, struct vb2_buffer *vb2
 		vb2_set_plane_payload(vb2, i, size);
 	}
 
+	v4l2_buf->field = pix->field;
+
 	return 0;
 }