Replaces Hans Verkuil by Andy Walls as the ivtv maintainer.

After 4 1/2 years, Hans decided to hand over the ivtv driver to Andy.
Andy was already doing more work on ivtv than him, so this just makes
official what was happening in practice.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>