iio: fix pressure data output unit in hid-sensor-attributes
According to IIO ABI definition, IIO_PRESSURE data output unit is
kilopascal:
http://lxr.free-electrons.com/source/Documentation/ABI/testing/sysfs-bus-iio
This patch fix output unit of HID pressure sensor IIO driver from pascal to
kilopascal to follow IIO ABI definition.