V4L/DVB: cx23885: Add correct detection of the HVR-1250 model 79501

The offset in the eeprom data for the 79501 version of the HVR-1250 is at 0xc0
vs. the standard 0x80.

Signed-off-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>