Move scroll button handling out of HandleState.
Move scroll button handling out of HandleState.

Again, just to make the code easier to read, no functional changes.

Signed-off-by: Peter Hutterer <b9c50af7afa7642f6f854434cda9ffe54ece8b85@who-t.net>
Reviewed-by: Jamey Sharp <167c1dcbbc9c320e8e02a0c15c886204b4e658a4@minilop.net>

mad-s/xf86-input-synaptics-absolute,mad-s/xf86-input-synaptics-absolute