backends/libinput: don't multiply v120 value by scroll speed

The value is a representation of the discrete steps a mouse wheel can take.
Multiplying that with a scroll speed destroys the whole purpose of the value.

src/backends/libinput/events.cpp

@@ -211,7 +211,7 @@ qint32 PointerEvent::scrollValueV120(InputRedirection::PointerAxis axis) const
     const libinput_pointer_axis a = (axis == InputRedirection::PointerAxisHorizontal)
         ? LIBINPUT_POINTER_AXIS_SCROLL_HORIZONTAL
         : LIBINPUT_POINTER_AXIS_SCROLL_VERTICAL;
-    return libinput_event_pointer_get_scroll_value_v120(m_pointerEvent, a) * device()->scrollFactor();
+    return libinput_event_pointer_get_scroll_value_v120(m_pointerEvent, a);
 }
 
 TouchEvent::TouchEvent(libinput_event *event, libinput_event_type type)