Print CMake messages on stdout rather than stderr

The default version of message("...") print to stderr, which is inappropriate
for informational messages such as the ones we are printing in these cases.

Using message(STATUS "...") makes these messages appear on stdout instead
which is more appropriate.

Change-Id: I02f41e6b4948e6938566f06d7164444bd5b8199e
Signed-off-by: Robert Hughes <robert.hughes@arm.com>
diff --git a/src/backends/backends.cmake b/src/backends/backends.cmake
index 473de48..aca3b63 100644
--- a/src/backends/backends.cmake
+++ b/src/backends/backends.cmake
@@ -10,13 +10,13 @@
 
 # prefer to include common code first
 foreach(includeFile ${commonIncludes})
-    message("Including backend common library into the build: ${includeFile}")
+    message(STATUS "Including backend common library into the build: ${includeFile}")
     include(${includeFile})
 endforeach()
 
 # now backends can depend on common code included first
 foreach(includeFile ${backendIncludes})
-    message("Including backend into the build: ${includeFile}")
+    message(STATUS "Including backend into the build: ${includeFile}")
     include(${includeFile})
 endforeach()
 
diff --git a/src/backends/cl/backend.cmake b/src/backends/cl/backend.cmake
index eb62147..9484b94 100644
--- a/src/backends/cl/backend.cmake
+++ b/src/backends/cl/backend.cmake
@@ -10,5 +10,5 @@
     list(APPEND armnnLibraries armnnClBackendWorkloads)
     list(APPEND armnnUnitTestLibraries armnnClBackendUnitTests)
 else()
-    message("CL backend is disabled")
+    message(STATUS "CL backend is disabled")
 endif()
diff --git a/src/backends/neon/backend.cmake b/src/backends/neon/backend.cmake
index c8ff488..801ba7c 100644
--- a/src/backends/neon/backend.cmake
+++ b/src/backends/neon/backend.cmake
@@ -10,5 +10,5 @@
     list(APPEND armnnLibraries armnnNeonBackendWorkloads)
     list(APPEND armnnUnitTestLibraries armnnNeonBackendUnitTests)
 else()
-    message("NEON backend is disabled")
+    message(STATUS "NEON backend is disabled")
 endif()
diff --git a/src/backends/reference/backend.cmake b/src/backends/reference/backend.cmake
index 01a4ee1..e8654d8 100644
--- a/src/backends/reference/backend.cmake
+++ b/src/backends/reference/backend.cmake
@@ -10,5 +10,5 @@
     list(APPEND armnnLibraries armnnRefBackendWorkloads)
     list(APPEND armnnUnitTestLibraries armnnRefBackendUnitTests)
 else()
-    message("Reference backend is disabled")
+    message(STATUS "Reference backend is disabled")
 endif()