[Android] Explicitly set the defaults for the CPU settings.

Source/Android/res/xml/cpu_prefs.xml

@@ -2,6 +2,7 @@
 <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
     <!-- CPU Settings -->
     <CheckBoxPreference
+        android:defaultValue="false"
         android:key="dualCorePref"
         android:summary="@string/dual_core_descrip"
         android:title="@string/dual_core" />
@@ -10,7 +11,9 @@
         android:key="cpuCorePref"
         android:summary="@string/emu_core_to_use"
         android:title="@string/cpu_core" />
+
     <CheckBoxPreference
+        android:defaultValue="false"
         android:key="fastmemPref"
         android:summary="@string/fastmem_desc"
         android:title="@string/fastmem" />