IVGCVSW-2049 Create the CL Mean Float workload

 * Added the missing CLReduceMean.cpp file to the Android mekfile

Change-Id: Ieaf7c056d6a5e705999a1daef63f5e78d5db3a37
diff --git a/Android.bp b/Android.bp
index 7f28e90..053c4fc 100644
--- a/Android.bp
+++ b/Android.bp
@@ -390,6 +390,7 @@
         "clframework/src/runtime/CL/functions/CLPixelWiseMultiplication.cpp",
         "clframework/src/runtime/CL/functions/CLPoolingLayer.cpp",
         "clframework/src/runtime/CL/functions/CLQuantizationLayer.cpp",
+        "clframework/src/runtime/CL/functions/CLReduceMean.cpp",
         "clframework/src/runtime/CL/functions/CLReductionOperation.cpp",
         "clframework/src/runtime/CL/functions/CLRemap.cpp",
         "clframework/src/runtime/CL/functions/CLReorgLayer.cpp",