V4L/DVB (4994): Vivi: fix use after free in list_for_each()

Freeing data including list_head in list_for_each() is not safe.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>