cppcheck: Suppress constParameterCallback errors

We have several functions which are used as callbacks for NS_CALL() which
only read their void * parameter, they don't write it.  The
constParameterCallback warning in cppcheck 2.14.1 complains that this
parameter could be const void *, also pointing out that that would require
casting the function pointer when used as a callback.

Casting the function pointers seems substantially uglier than using a
non-const void * as the parameter, especially since in each case we cast
the void * to a const pointer of specific type immediately.  So, suppress
these errors.

I think it would make logical sense to suppress this globally, but that
would cause unmatchedSuppression errors on earlier cppcheck versions.  So,
instead individually suppress it, along with unmatchedSuppression in the
relevant places.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

tcp.c

@@ -3079,6 +3079,7 @@ void tcp_ns_sock_init(const struct ctx *c, in_port_t port)
  *
  * Return: 0
  */
+/* cppcheck-suppress [constParameterCallback, unmatchedSuppression] */
 static int tcp_ns_socks_init(void *arg)
 {
 	const struct ctx *c = (const struct ctx *)arg;