V4L/DVB (4639): Cx88: add autodetection for alternate revision of Leadtek PVR

Add autodetection for PCI subsystem ID 107d:6632, to detect as
a Leadtek PVR 2000

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>