[media] ddbridge: Avoid duplicated symbol definition

drivers/media/dvb/ddbridge/built-in.o: In function `my_dvb_dmx_ts_card_init':
/home/v4l/v4l/patchwork/drivers/media/dvb/ddbridge/ddbridge-core.c:718: multiple definition of `my_dvb_dmx_ts_card_init'
drivers/media/dvb/ngene/built-in.o:/home/v4l/v4l/patchwork/drivers/media/dvb/ngene/ngene-dvb.c:227: first defined here
drivers/media/dvb/ddbridge/built-in.o: In function `my_dvb_dmxdev_ts_card_init':
/home/v4l/v4l/patchwork/drivers/media/dvb/ddbridge/ddbridge-core.c:737: multiple definition of `my_dvb_dmxdev_ts_card_init'
drivers/media/dvb/ngene/built-in.o:/home/v4l/v4l/patchwork/drivers/media/dvb/ngene/ngene-dvb.c:246: first defined here

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