COMPMID-518 - Bare metal support

Change-Id: Ida6d3dc46476fd9a67b5860e5e5bf8b848a8ac23
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/85981
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
Reviewed-by: Moritz Pflanzer <moritz.pflanzer@arm.com>
diff --git a/src/core/NEON/kernels/NEHistogramKernel.cpp b/src/core/NEON/kernels/NEHistogramKernel.cpp
index 9e967ec..2018651 100644
--- a/src/core/NEON/kernels/NEHistogramKernel.cpp
+++ b/src/core/NEON/kernels/NEHistogramKernel.cpp
@@ -44,7 +44,7 @@
 
 inline void NEHistogramKernel::merge_histogram(uint32_t *global_hist, const uint32_t *local_hist, size_t bins)
 {
-    std::lock_guard<std::mutex> lock(_hist_mtx);
+    std::lock_guard<arm_compute::Mutex> lock(_hist_mtx);
 
     const unsigned int v_end = (bins / 4) * 4;