V4L/DVB (12712): em28xx: properly load ir-kbd-i2c when needed

Currently, the logic to load ir i2c ancillary module is broken. It is
associated to Hauppauge devices with IR flag on their eeprom, no matter
if the device uses i2c or em28xx direct IR support. That's wrong.

Instead, add a flag to the boards that use i2c IR chips and load the
module only for those devices and if ir is not disabled.

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