tty: drop tty_schedule_flip()

stable inclusion
from stable-v5.10.134
commit c84986d097451203bb79a8bff8d37e56488fbf1d
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5A5Y1
CVE: CVE-2022-1462

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c84986d097451203bb79a8bff8d37e56488fbf1d



--------------------------------

commit 5db96ef2 upstream.

Since commit a9c3f68f (tty: Fix low_latency BUG) in 2014,
tty_flip_buffer_push() is only a wrapper to tty_schedule_flip(). All
users were converted in the previous patches, so remove
tty_schedule_flip() completely while inlining its body into
tty_flip_buffer_push().

One less exported function.

Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211122111648.30379-4-jslaby@suse.cz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yi Yang <yiyang13@huawei.com>
Reviewed-by: Wang Weiyang <wangweiyang2@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>