V4L/DVB (13204): saa7134: add support for the Leadtek DTV1000S

Thanks to Terry Wu for finding the GPIOs required for svideo / composite input

Cc: Terry Wu <terrywu2009@gmail.com>
Signed-off-by: Michael Krufky <mkrufky@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>