media: staging: media: zoran: fix TRY_FMT handling

TRY_FMT must not set actual capture values (zr->buffer_size in
this case), since it is a 'try' only.

zoran_try_fmt_vid_cap() also didn't fill in fmt->fmt.pix.bytesperline
and fmt->fmt.pix.sizeimage correctly.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>