Fix bpf_map_update_elem prototype used by the verifier (#781)

It had four arguments in:
* https://github.com/microsoft/ebpf-for-windows/blob/master/include/bpf_helper_defs.h#L33
* https://github.com/microsoft/ebpf-for-windows/blob/master/libs/execution_context/ebpf_core.c#L1261

but only three arguments in ebpf_general_helpers.c

Signed-off-by: Dave Thaler <dthaler@microsoft.com>

libs/execution_context/ebpf_general_helpers.c

@@ -18,7 +18,10 @@ ebpf_helper_function_prototype_t ebpf_core_helper_function_prototype_array[] = {
     {BPF_FUNC_map_update_elem,
      "bpf_map_update_elem",
      EBPF_RETURN_TYPE_INTEGER,
-     {EBPF_ARGUMENT_TYPE_PTR_TO_MAP, EBPF_ARGUMENT_TYPE_PTR_TO_MAP_KEY, EBPF_ARGUMENT_TYPE_PTR_TO_MAP_VALUE}},
+     {EBPF_ARGUMENT_TYPE_PTR_TO_MAP,
+      EBPF_ARGUMENT_TYPE_PTR_TO_MAP_KEY,
+      EBPF_ARGUMENT_TYPE_PTR_TO_MAP_VALUE,
+      EBPF_ARGUMENT_TYPE_ANYTHING}},
     {BPF_FUNC_map_delete_elem,
      "bpf_map_delete_elem",
      EBPF_RETURN_TYPE_INTEGER,
@@ -62,4 +65,4 @@ extern "C"
 
 #ifdef __cplusplus
 }
-#endif
+#endif