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/fuelgauge/PowerGaugePreference.java

@@ -37,7 +37,7 @@ public class PowerGaugePreference extends Preference {
 
     public PowerGaugePreference(Context context, Drawable icon, BatteryEntry info) {
         super(context);
-        setLayoutResource(R.layout.app_percentage_item);
+        setLayoutResource(R.layout.preference_app_percentage);
         setIcon(icon != null ? icon : new ColorDrawable(0));
         mInfo = info;
     }