[media] drx-j: reset the DVB scan configuration at powerup

Without this fixup, the DRX-J will not be properly initialized,
loosing several PIDs.

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