pata_isapnp: Don't use invalid I/O ports

The test for 2nd I/O port validity is broken (reversed): On devices
with no control port, the driver attempts to use invalid port 0,
resulting in logs full of bad_io_access errors.  On devices with
control port, the driver does not use it.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Tejun Heo <tj@kernel.org>