Fix build error v8.2-a-sve

* bf16 instrinsics should be used when __ARM_FEATURE_SVE_BF16 is present

* Fixed NDK14 compiler warning declaring copy ctor for Window explicitly

* Resolves MLCE-867

Change-Id: I84ac5f213d9700e2fda7da55d83bba7cf79ad52c
Signed-off-by: Pablo Marquez Tello <pablo.tello@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/7728
Reviewed-by: Michalis Spyrou <michalis.spyrou@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
diff --git a/arm_compute/core/Window.h b/arm_compute/core/Window.h
index c566cff..440b942 100644
--- a/arm_compute/core/Window.h
+++ b/arm_compute/core/Window.h
@@ -90,6 +90,7 @@
             : _start(start), _end(end), _step(step)
         {
         }
+        Dimension(const Dimension &d) = default;
         /** Default assignment operator to allow dimensions to be copied */
         Dimension &operator=(const Dimension &d) = default;
         /** Return the start of the dimension */