media: zoran: remove unused declarations in zoran_device.h

jpg_bufsize and v4l_bufsize have been removed since
commit 202ddbc9

 ("media: staging: media: zoran:
clean unused code"), so remove them.

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>