[media] se401: remove last V4L1 driver

This driver is for obsolete hardware that the old maintainer
didn't care (or not have the hardware anymore), and that no other developer
could find any hardware to buy.

The V4L1 API is no longer supported, and since nobody stepped in to convert
them to V4L2 the decision was made to remove them.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>