[media] drx-j: remove some ugly bindings from drx39xxj_dummy.c

This file does an ugly binding between drxj and DVB frontend.

Remove most of the functions there. We still need to get rid of
get_frequency and set_frequency, but such patch is a little more
complex, as it should also remove some previous tuner bindings.

Acked-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>