V4L/DVB (9753): em28xx: cleanup: saa7115 module auto-detects saa711x type

Since saa7115 has saa711x chip auto-detection, there's no need on differenciating
it at cards table. Just use the generic name for all boards that use a philips
saa711x decoder.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>