COMPMID-2451: Use kernel lws_hint() on enqueue

Avoid querying device's default lws on kernel enqueue as this is already
cached in the kernel during configuration.

Change-Id: Ia26ecb712caeb8f042356815e0cfd23522764d27
Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>
Reviewed-on: https://review.mlplatform.org/c/1803
Reviewed-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/core/CL/kernels/CLPriorBoxLayerKernel.cpp b/src/core/CL/kernels/CLPriorBoxLayerKernel.cpp
index c76d839..12ea193 100644
--- a/src/core/CL/kernels/CLPriorBoxLayerKernel.cpp
+++ b/src/core/CL/kernels/CLPriorBoxLayerKernel.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018 ARM Limited.
+ * Copyright (c) 2018-2019 ARM Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -214,6 +214,6 @@
 
     unsigned int idx = 0;
     add_2D_tensor_argument(idx, _output, slice);
-    enqueue(queue, *this, slice);
+    enqueue(queue, *this, slice, lws_hint());
 }
 } // namespace arm_compute