tty: tty_port: Add IO_ERROR bit handling

To propogate tty_port_open/close to a few other devices we need to start
handling the IO_ERROR flag on the tty. We can do this pretty trivially.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>