cdc-acm: fix BREAK rx code path adding necessary calls

stable inclusion
from stable-5.10.28
commit e700e3aec303597851f3113b0837fde7af44223f
bugzilla: 51779

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

commit 08dff274 upstream.

Counting break events is nice but we should actually report them to
the tty layer.

Fixes: 5a6a62bd ("cdc-acm: add TIOCMIWAIT")
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20210311133714.31881-1-oneukum@suse.com


Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by:   Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>