TODO: Remove in late 2019 unless there are users


I tried to find any indication of whether the capi drivers are
still in use, and have not found anything  from a long time ago.

With public ISDN networks almost completely shut down over the past 12
months, there is very little you can actually do with this hardware. The
main remaining use case would be to connect ISDN voice phones to an
in-house installation with Asterisk or LCR, but anyone trying this in
turn seems to be using either the mISDN driver stack, or out-of-tree
drivers from the hardware vendors.

I may of course have missed something, so I would suggest moving
these into drivers/staging/ just in case someone still uses one
of the three remaining in-kernel drivers (avm, hysdn, gigaset).

If nobody complains, we can remove them entirely in six months,
or otherwise move the core code and any drivers that are still
needed back into drivers/isdn.

  Arnd Bergmann <arnd@arndb.de>
