Add support for CLVK

This patch enables CLVK through the graph API and inside the
CLScheduler. By default the Native platform is selected.
Selecting CLVK can be done via --target=clvk.

Resolves COMPMID-4205 and COMPMID-4206

Change-Id: Ic60744980c6b8a60e776627ea677ed46be88f656
Signed-off-by: Michalis Spyrou <michalis.spyrou@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/5475
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
diff --git a/arm_compute/core/CL/OpenCL.h b/arm_compute/core/CL/OpenCL.h
index 155c3e4..1e6b04c 100644
--- a/arm_compute/core/CL/OpenCL.h
+++ b/arm_compute/core/CL/OpenCL.h
@@ -123,6 +123,7 @@
     DECLARE_FUNCTION_PTR(clGetDeviceIDs);
     DECLARE_FUNCTION_PTR(clGetMemObjectInfo);
     DECLARE_FUNCTION_PTR(clRetainEvent);
+    DECLARE_FUNCTION_PTR(clGetPlatformInfo);
     DECLARE_FUNCTION_PTR(clGetPlatformIDs);
     DECLARE_FUNCTION_PTR(clGetKernelWorkGroupInfo);
     DECLARE_FUNCTION_PTR(clGetCommandQueueInfo);