[media] saa7164: Add support for another HVR2200 hardware revision

Hauppauge have released a new model rev, sub id 8940, this adds
support.

[stoth@kernellabs.com: I modified Tony's patch slightly in relation to the
 card numbering in saa7164.h, appending rather than inserting the new card
 - normal practise]
Signed-off-by: Tony Jago <tony@hammertelecom.com.au>
Signed-off-by: Steven Toth <stoth@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>