ImmediateInterpreter: Fix Max Finger Stationary Speed units

Fix the units for this. They were mm/sqrt(s), but should be mm/s. For
a more complete description, see the corresponding CL in the xorg-conf
repo.

BUG=chromium:242656
TEST=Magic Mouse regression tests pass, manually tested magic mouse

Change-Id: I45944ac6e05ea21d9c1be4b9333c02ae2876f232
Reviewed-on: https://chromium-review.googlesource.com/225453
Reviewed-by: Dennis Kempin <denniskempin@chromium.org>
Tested-by: Andrew de los Reyes <adlr@chromium.org>
Commit-Queue: Andrew de los Reyes <adlr@chromium.org>
diff --git a/src/immediate_interpreter.cc b/src/immediate_interpreter.cc
index dfb075e..0b42d2f 100644
--- a/src/immediate_interpreter.cc
+++ b/src/immediate_interpreter.cc
@@ -420,7 +420,7 @@
                     (current.position_x - prev->position_x) +
                     (current.position_y - prev->position_y) *
                     (current.position_y - prev->position_y);
-    float dist_sq_thresh = duration *
+    float dist_sq_thresh = duration * duration *
         max_stationary_speed_.val_ * max_stationary_speed_.val_;
     if (dist_sq > dist_sq_thresh)
       return false;