[media] drx-j: remove unused code from drx_driver.c

There are several drx-j code there that are never used, as
they don't even fit into Linux DVB subystem model.

Remove them, in order to simplify the code.

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