Fix icon size for Data Usage / Battery Stats / Process Stats

- remove padding from app_percentage_item and apply it correctly
on its containers
- wrap app_percentage_item into preference_app_percentage for having
correct padding o nProcessStatsPreference and PowerGaugePreference

Change-Id: I290c92959f51a33a1edb49435cd0bd1e6cd9afa3

src/com/android/settings/applications/ProcessStatsPreference.java

@@ -47,7 +47,7 @@ public class ProcessStatsPreference extends Preference {
     public ProcessStatsPreference(Context context, AttributeSet attrs, int defStyleAttr,
             int defStyleRes) {
         super(context, attrs, defStyleAttr, defStyleRes);
-        setLayoutResource(R.layout.app_percentage_item);
+        setLayoutResource(R.layout.preference_app_percentage);
     }
 
     public void init(Drawable icon, ProcStatsEntry entry) {