evdev: remove direct checks for INPUT_PROP_POINTING_STICK

evdev: remove direct checks for INPUT_PROP_POINTING_STICK

If we need to temporary override a device with ID_INPUT_POINTINGSTICK,
evdev sets the tag EVDEV_TAG_TRACKPOINT to the device. Rely on the tag
to behave properly for scroll emulation.

The dpi information should be retrieved after the device has been
configured or the tag EVDEV_TAG_TRACKPOINT was not set.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>