COMPMID-2177 Fix clang warnings

Change-Id: I78039db8c58d7b14a042c41e54c25fb9cb509bf7
Signed-off-by: Michalis Spyrou <michalis.spyrou@arm.com>
Reviewed-on: https://review.mlplatform.org/c/1092
Reviewed-by: VidhyaSudhan Loganathan <vidhyasudhan.loganathan@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
diff --git a/arm_compute/runtime/CL/functions/CLStackLayer.h b/arm_compute/runtime/CL/functions/CLStackLayer.h
index 5b821b8..30676e1 100644
--- a/arm_compute/runtime/CL/functions/CLStackLayer.h
+++ b/arm_compute/runtime/CL/functions/CLStackLayer.h
@@ -73,9 +73,9 @@
     void run() override;
 
 private:
-    std::vector<ICLTensor *>              _input;
-    std::unique_ptr<CLStackLayerKernel[]> _stack_kernels;
-    unsigned int                          _num_inputs;
+    std::vector<ICLTensor *>        _input;
+    std::vector<CLStackLayerKernel> _stack_kernels;
+    unsigned int                    _num_inputs;
 };
 } // namespace arm_compute
 #endif /* __ARM_COMPUTE_CLSTACKLAYER_H__ */