sandbox: Disable mmio by default in tests

When reseting sandbox for tests, disable mmio support since that is the
default state.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

arch/sandbox/cpu/state.c

@@ -356,6 +356,7 @@ void state_reset_for_test(struct sandbox_state *state)
 	/* No reset yet, so mark it as such. Always allow power reset */
 	state->last_sysreset = SYSRESET_COUNT;
 	state->sysreset_allowed[SYSRESET_POWER_OFF] = true;
+	state->allow_memio = false;
 
 	memset(&state->wdt, '\0', sizeof(state->wdt));
 	memset(state->spi, '\0', sizeof(state->spi));