Remove use of boost from Logging.hpp

This helps prevent leaking of boost names into Arm NN public headers.

Change-Id: I1605d2ed178965f8e502bc6a4b4ac3e627bbbbed
Signed-off-by: Matthew Bentham <Matthew.Bentham@arm.com>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index f5d4165..8616d6d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -382,6 +382,7 @@
     src/armnn/LayerSupport.cpp
     src/armnn/LoadedNetwork.cpp
     src/armnn/LoadedNetwork.hpp
+    src/armnn/Logging.cpp
     src/armnn/Network.cpp
     src/armnn/Network.hpp
     src/armnn/NetworkQuantizationScheme.hpp