tty: ircomm: remove dead and broken ioctl code

Remove three ifdefed and broken implementations of TIOCSSERIAL and
TIOCGICOUNT, and parity handling in set_termios which had suffered
severe bit rot.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>