ggml-cpu: Update KleidiAI to v1.6 and fix include directives (#13509)

Signed-off-by: Dan Johansson <dan.johansson@arm.com>

ggml/src/ggml-cpu/kleidiai/kernels.h

@@ -5,6 +5,7 @@
 #pragma once
 
 #include <functional>
+#include <variant>
 #include "ggml.h"
 
 enum cpu_feature {

ggml/src/ggml-cpu/kleidiai/kleidiai.cpp

@@ -3,7 +3,9 @@
 //
 #include <arm_neon.h>
 #include <assert.h>
+#include <atomic>
 #include <cfloat>
+#include <stdexcept>
 #include <stdint.h>
 #include <string.h>
 #if defined(__linux__)