IVGCVSW-1806 More Android NN Driver refactoring

 * Changed #if defined to #ifdef
 * Simplified the Android ML namespace resolution
 * Fixed the relative path in some include directives

Change-Id: I46e46faff98559c8042c1a4b8b82007f462df57d
diff --git a/RequestThread.cpp b/RequestThread.cpp
index 0b06b51..4731489 100644
--- a/RequestThread.cpp
+++ b/RequestThread.cpp
@@ -137,7 +137,7 @@
 
 template class RequestThread<hal_1_0::HalPolicy>;
 
-#if defined(ARMNN_ANDROID_NN_V1_1)
+#ifdef ARMNN_ANDROID_NN_V1_1
 template class RequestThread<hal_1_1::HalPolicy>;
 #endif