dvb_unregister_device() has a major problem: it combines unregistering
with memory disposal. Sometimes, it is necessary to unregister a
device, but no memory can be freed yet, because a process still has a
(stale) file handle. Therefore, we need to split
dvb_unregister_device(). This will allow sanitizing a few callers.
With my new design, dvb_unregister_device() appears misnamed, but to
reduce patch noise, I'm not renaming it just yet.
Signed-off-by: Max Kellermann <max.kellermann@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>