Update CPU kernel implementations and guard directives

Resolves COMPMID-6023

Change-Id: I868975d14c4f98af6716726feda22405a6a4c891
Signed-off-by: Michael Tyler <michael.tyler@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/9686
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Viet-Hoa Do <viet-hoa.do@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/core/NEON/kernels/arm_gemm/transforms/a64_transpose_interleave_16.hpp b/src/core/NEON/kernels/arm_gemm/transforms/a64_transpose_interleave_16.hpp
index f06c167..0399f8b 100644
--- a/src/core/NEON/kernels/arm_gemm/transforms/a64_transpose_interleave_16.hpp
+++ b/src/core/NEON/kernels/arm_gemm/transforms/a64_transpose_interleave_16.hpp
@@ -24,7 +24,7 @@
 
 #pragma once
 
-#ifdef __aarch64__
+#if defined(__aarch64__)
 
 namespace {
 
@@ -137,4 +137,5 @@
     );
 }
 
-#endif
+
+#endif  // defined(__aarch64__)