IVGCVSW-6847 replace armnn:Optional with arm::pipe::Optional in profiling code

Change-Id: I048c538d4f8c21770aec2b2751c934d9fa15a4dc
Signed-off-by: Jim Flynn <jim.flynn@arm.com>
diff --git a/src/profiling/DirectoryCaptureCommandHandler.cpp b/src/profiling/DirectoryCaptureCommandHandler.cpp
index ac11f68..4011c9b 100644
--- a/src/profiling/DirectoryCaptureCommandHandler.cpp
+++ b/src/profiling/DirectoryCaptureCommandHandler.cpp
@@ -289,7 +289,7 @@
                                                                              descriptionOffset +
                                                                              uint32_t_size);
 
-        eventRecords[i].m_CounterUnits = unitsOffset == 0 ? armnn::Optional<std::string>() :
+        eventRecords[i].m_CounterUnits = unitsOffset == 0 ? arm::pipe::Optional<std::string>() :
                 GetStringNameFromBuffer(data, eventRecordsOffsets[i] + offset + unitsOffset + uint32_t_size);
     }