[Nightly Failure] Fix NEIm2Col argument validation errors

- Permute input shape if NHWC for Im2Col's fixture

Resolves: COMPMID-4081

Signed-off-by: Giorgio Arena <giorgio.arena@arm.com>
Change-Id: I9a46569f1cb2c09932ffb1b0afda6d66e93452de
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/4777
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/tests/validation/fixtures/Im2ColFixture.h b/tests/validation/fixtures/Im2ColFixture.h
index e1f33a3..b6cf18b 100644
--- a/tests/validation/fixtures/Im2ColFixture.h
+++ b/tests/validation/fixtures/Im2ColFixture.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2020 Arm Limited.
+ * Copyright (c) 2017-2021 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -59,6 +59,11 @@
         _has_bias    = data_type != DataType::QASYMM8;
         _num_groups  = num_groups;
 
+        if(_data_layout == DataLayout::NHWC)
+        {
+            permute(input_shape, PermutationVector(2U, 0U, 1U));
+        }
+
         TensorInfo input_info(input_shape, 1, data_type);
         input_info.set_data_layout(_data_layout);