commit 0cbd81a9 upstream.

Fixes tty_flip_buffer_push being called from hard interrupt context with
low_latency set.
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>