Remove padding from ClDirectConv2dKernel

- Delete old NCHW ClDirectConv2d kernels.
- Merge all kernels on a single file.
- Removed padding from ClDirectConv2dKernel

Resolves COMPMID-4721

Signed-off-by: Adnan AlSinan <adnan.alsinan@arm.com>
Change-Id: I624d218fb770e7b5f3c0acd4e85a21ae48470f55
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/6779
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Gian Marco Iodice <gianmarco.iodice@arm.com>
diff --git a/SConscript b/SConscript
index a8995ac..7e90101 100644
--- a/SConscript
+++ b/SConscript
@@ -353,10 +353,7 @@
                     'src/core/CL/cl_kernels/nchw/batchnormalization_layer.cl',
                     'src/core/CL/cl_kernels/nchw/channel_shuffle.cl',
                     'src/core/CL/cl_kernels/nchw/depth_to_space.cl',
-                    'src/core/CL/cl_kernels/nchw/direct_convolution_quantized.cl',
-                    'src/core/CL/cl_kernels/nchw/direct_convolution1x1.cl',
-                    'src/core/CL/cl_kernels/nchw/direct_convolution3x3.cl',
-                    'src/core/CL/cl_kernels/nchw/direct_convolution5x5.cl',
+                    'src/core/CL/cl_kernels/nchw/direct_convolution.cl',
                     'src/core/CL/cl_kernels/nchw/dequantization_layer.cl',
                     'src/core/CL/cl_kernels/nchw/im2col.cl',
                     'src/core/CL/cl_kernels/nchw/normalization_layer.cl',