usb: Un-deprecate -usbdevice (except for -usbdevice audio which gets removed)

When trying to remove the -usbdevice option, there were complaints that
"-usbdevice braille" is still a very useful shortcut for some people.
Thus we never remove this option. Since it's not such a big burden to
keep it around, and it's also convenient in the sense that you don't
have to worry to enable a host controller explicitly with this option,
we should remove it from he deprecation list again.

However, there is one exception: "-usbdevice audio" should go away, since
audio devices without "audiodev=..." parameter are also on the deprecation
list and you cannot use "-usbdevice audio" with "audiodev".

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210310173323.1422754-4-thuth@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>