TTY: ldisc, move wait idle to caller

TTY: ldisc, move wait idle to caller

commit 300420722e0734a4254f3b634e0f82664495d210 upstream.

It is the only place where reinit is called from. And we really need
to wait for the old ldisc to go once. Actually this is the place where
the waiting originally was (before removed and re-added later).

This will make the fix in the following patch easier to implement.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Dave Young <hidave.darkstar@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Dmitriy Matrosov <sgf.dma@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>