[media] zoran: remove bogus autodetect mode in set_norm

Currently, if the norm set is V4L2_STD_ALL, then autodetect the current
standard and use that. This is non-standard behavior, and in fact it hasn't
worked for a very long time: before s_std is called in this driver, the
v4l2 core will mask it with the tvnorms field. So even if the application
passes V4L2_STD_ALL, the zoran driver will always see a subset of that.
Since nobody ever complained about this we just remove this non-standard
functionality.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>