Fix Brushes with deformation target being affected by sim areas

Brushes that target the cloth simulation but are not the cloth brush
affect the entire mesh, so they don't have simulation areas and falloff.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D8885

source/blender/editors/sculpt_paint/sculpt_cloth.c

@@ -108,6 +108,11 @@ static float cloth_brush_simulation_falloff_get(const Brush *brush,
                                                 const float location[3],
                                                 const float co[3])
 {
+  if (brush->sculpt_tool != SCULPT_TOOL_CLOTH) {
+    /* All brushes that are not the cloth brush do not use simulation areas. */
+    return 1.0f;
+  }
+
   /* Global simulation does not have any falloff as the entire mesh is being simulated. */
   if (brush->cloth_simulation_area_type == BRUSH_CLOTH_SIMULATION_AREA_GLOBAL) {
     return 1.0f;