V4L/DVB (5025): Cleanup: switch to using msecs_to_jiffies() on bttv

PS.: Part of the changes at the original patch were removed due to the changes
done at commit 52c14e794f6ce345343a6b8fc98ea4e0ba2dfce4

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>