filter: normalize deltas before processing or returning them

When the filter code switched to raw device coordinates (bdd4264d) the input
data remained in device coordinates. Since the factor for touchpads was still
based on the physical velocity (and thus all touchpads get the same
acceleration factor for identical moves), the actual delta was dependent on
the resolution. e.g.

touchpad with 40u/mm: delta of 2/2 * accel factor 2 -> accel delta of 4/4
touchpad with 20u/mm: delta of 1/1 * accel factor 2 -> accel delta of 2/2

The normalized coordinates should be independent of the touchpad's resolution
though.

Affected by this was the standard mouse accel code and the touchpad accel
code, other filters always returned unnormalized coordinates (separate bug,
not addressed here).

This patch restores the correct behaviour for mice and touchpads
while leaving the special filters untouched. For comparision:
* 1000+dpi mice: accelerate normalized, return normalized
* touchpads: accelerate unnormalized, return normalized
* low-dpi mice: accelerate unnormalized, return unnormalized
* trackpoints: accelerate unnormalized, return unnormalized
* x230: don't touch, already does the right thing

https://bugs.freedesktop.org/show_bug.cgi?id=99383

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>

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