At present when pressing Ctrl+C from a guest running on QEMU Windows
with a multiplexed monitor, e.g.: -serial mon:stdio, QEMU executable
just exits. This behavior is inconsistent with the Linux version.

Such behavior is caused by unconditionally setting the input mode
ENABLE_PROCESSED_INPUT for a console's input buffer. Fix this by
testing whether the chardev is allowed to do so.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20221025141015.612291-1-bin.meng@windriver.com>