evdev: Don't transform device->abs.x/y in place

evdev: Don't transform device->abs.x/y in place

We don't always get both an X and an Y event in a SYN report, so we end
up transforming the coordinate we don't get twice.  For example, if we
only receive an ABS_X event, we transform the already transformed
device->abs.y again in transform_absolute() when applying the calibration.