rtc: rtctest: enabling UIE for a chip that doesn't support it returns EINVAL

Calling ioctl(..., RTC_UIE_ON, ...) without CONFIG_RTC_INTF_DEV_UIE_EMUL
either ends in rtc_update_irq_enable if rtc->uie_unsupported is true
or in __rtc_set_alarm in the if (!rtc->ops->set_alarm) branch. In both
cases the return value is -EINVAL. So check for that one instead of
ENOTTY.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

tools/testing/selftests/timers/rtctest.c

@@ -61,7 +61,7 @@ int main(int argc, char **argv)
 	/* Turn on update interrupts (one per second) */
 	retval = ioctl(fd, RTC_UIE_ON, 0);
 	if (retval == -1) {
-		if (errno == ENOTTY) {
+		if (errno == EINVAL) {
 			fprintf(stderr,
 				"\n...Update IRQs not supported.\n");
 			goto test_READ;