iBasso DX50/DX90: User selectable freq scaling governor.

Depends on http://gerrit.rockbox.org/r/#/c/1043/.

This patch adds a new setting in Settings -> General
-> System: Freq Scaling Governor

Usable in Quickscreen and Shortcuts.

Possible settings are:
- Conservative: Slow frequency switching.
- Ondemand or Interactive: Fast frequency switching.
- Powersave: Allways lowest frequency.
- Performance: Allways highest frequency.

German translation provided.

This may be genric for Android kernel based devices but is only enabled
for iBasso Devices. Other maintainers may choose do adopt this.

Change-Id: I10296f5be9586ad3a409105db0cd03682a30e9c1

apps/lang/deutsch.lang

@@ -33,6 +33,7 @@
 # - Kaspar Rothenfußer
 # - Johannes Linke
 # - Kai Posadowsky
+# - Udo Schläpfer
 <phrase>
   id: LANG_SET_BOOL_YES
   desc: bool true representation
@@ -13054,3 +13055,23 @@
     *: "Beschränke automatischen Verzeichniswechsel"
   </voice>
 </phrase>
+<phrase>
+  id: LANG_IBASSO_FREQ_SCALING_GOVERNOR
+  desc: in Settings -> General -> System -> Freq Scaling Governor
+  user: core
+  <source>
+    *: none
+    ibassodx50: "Freq Scaling Governor"
+    ibassodx90: "Freq Scaling Governor"
+  </source>
+  <dest>
+    *: none
+    ibassodx50: "Freq Scaling Governor"
+    ibassodx90: "Freq Scaling Governor"
+  </dest>
+  <voice>
+    *: none
+    ibassodx50: "Freq Scaling Governor"
+    ibassodx90: "Freq Scaling Governor"
+  </voice>
+</phrase>

apps/lang/english.lang

@@ -13373,3 +13373,23 @@
     swcodec: "Dry / Wet Mix"
   </voice>
 </phrase>
+<phrase>
+  id: LANG_IBASSO_FREQ_SCALING_GOVERNOR
+  desc: in Settings -> General -> System -> Freq Scaling Governor
+  user: core
+  <source>
+    *: none
+    ibassodx50: "Freq Scaling Governor"
+    ibassodx90: "Freq Scaling Governor"
+  </source>
+  <dest>
+    *: none
+    ibassodx50: "Freq Scaling Governor"
+    ibassodx90: "Freq Scaling Governor"
+  </dest>
+  <voice>
+    *: none
+    ibassodx50: "Freq Scaling Governor"
+    ibassodx90: "Freq Scaling Governor"
+  </voice>
+</phrase>