We must unregister frontend first and after that driver itself. That
order went wrong after demod drivers were switched to kernel I2C
drivers, causing crashes.
Tested-by: NBenjamin Larsson <benjamin@southpole.se>
Signed-off-by: NAntti Palosaari <crope@iki.fi>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>