V4L/DVB (11253): saa7134: fix RTD Embedded Technologies VFG7350 support.

This card has the saa6752hs on 7-bit address 0x21 instead of 0x20. Add
support in the card definition struct to select which address to use and
update the definitions accordingly.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>