[media] drx-j: get rid of drx_ctrl

This function is used only as an abstraction layer to call the
two firmware functions. Remove it.

As a bonus, the drx_ctrl_function is now unused and can be
removed.

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