Declare `ConversionResult` in `android` namespace

Previously the declaration was depending on the `BACKEND_NDK`
define, and `ConversionResult` could end up in the `aidl` NS
(::aidl::ConversionResult). Having it in `android` is more
convenient as it works for nested namespaces of `android`, for
example `android::effect`.

Added alias `aidl::android::ConversionResult` for the NDK
backend case.

Bug: 205884982
Test: m
Change-Id: Ic3238144d35afb86db57d5d620f2f28ccd89021e
Merged-In: Ic3238144d35afb86db57d5d620f2f28ccd89021e
diff --git a/media/libaudiohal/impl/effectsAidlConversion/AidlConversionEq.h b/media/libaudiohal/impl/effectsAidlConversion/AidlConversionEq.h
index 2509c20..f94556c 100644
--- a/media/libaudiohal/impl/effectsAidlConversion/AidlConversionEq.h
+++ b/media/libaudiohal/impl/effectsAidlConversion/AidlConversionEq.h
@@ -33,10 +33,10 @@
   private:
     status_t setParameter(utils::EffectParamReader& param) override;
     status_t getParameter(utils::EffectParamWriter& param) override;
-    aidl::ConversionResult<::aidl::android::hardware::audio::effect::Parameter> getAidlParameter(
+    ConversionResult<::aidl::android::hardware::audio::effect::Parameter> getAidlParameter(
             ::aidl::android::hardware::audio::effect::Equalizer::Tag tag);
-    aidl::ConversionResult<int32_t> getParameterPreset();
-    aidl::ConversionResult<std::string> getParameterPresetName(utils::EffectParamWriter& param);
+    ConversionResult<int32_t> getParameterPreset();
+    ConversionResult<std::string> getParameterPresetName(utils::EffectParamWriter& param);
 };
 
 }  // namespace effect