accel/tcg: Update run_on_cpu_data static assert

As we are now using vaddr for representing guest addresses, update the
static assert to check that vaddr fits in the run_on_cpu_data union.

Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230807155706.9580-10-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>