pch_uart: Fix parity setting issue

Parity Setting value is reverse.
E.G. In case of setting ODD parity, EVEN value is set.
This patch inverts "if" condition.

Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>