V4L/DVB (3161): ir-kbd-gpio is now part of bttv

- Merged ir-kbd-gpio into bttv as bttv-input, for consistency with other
input modules

Signed-off-by: Ricardo Cerqueira <v4l@cerqueira.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>