Implement FP32/FP16 MatMul NT/T kernel using the MMUL extension

Resolves COMPMID-6195
Signed-off-by: ramy.elgammal@arm.com <ramy.elgammal@arm.com>
Change-Id: I8e85fe73308ed84ebb142d6d6d1562b62dddfaa5
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/9819
Reviewed-by: SiCong Li <sicong.li@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/gpu/cl/kernels/ClMatMulNativeMMULKernel.h b/src/gpu/cl/kernels/ClMatMulNativeMMULKernel.h
index 26fe08c..79f675d 100644
--- a/src/gpu/cl/kernels/ClMatMulNativeMMULKernel.h
+++ b/src/gpu/cl/kernels/ClMatMulNativeMMULKernel.h
@@ -86,6 +86,7 @@
 private:
     int _m{ 1 };
     int _n{ 1 };
+    int _k{ 1 };
 };
 } // namespace kernels
 } // namespace opencl