[media] drx-j: get rid of drxj_ctrl()

With this change, we finally got rid of all abstraction
layers on this driver.

This patch also fixes the LNA GPIO settings, as the original
code were using a wrong control name for it.

This patch exposes the several functions that aren't used.
Some of them are related to analog demod that might be
used some day, but others will likely never be needed, as
they don't fit on Linux media APIs.

Latter patches will clean up this mess.

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