Enable test for RT700 irtc driver.

1. Update overlay and project conf for RT700.
2. Update test_alarm.c to disable RTC irq so that callback function won't be called to clear the pending interrupt.

Signed-off-by: Holt.Sun <holt.sun@nxp.com>

Author: Holt-Sun

tests/drivers/rtc/rtc_api/boards/mimxrt700_evk_mimxrt798s_cm33_cpu0.conf

@@ -0,0 +1,2 @@
+CONFIG_RTC_ALARM=y
+CONFIG_TEST_RTC_ALARM_TIME_MASK=63

tests/drivers/rtc/rtc_api/boards/mimxrt700_evk_mimxrt798s_cm33_cpu0.overlay

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2025 NXP
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+/ {
+	aliases {
+		rtc = &rtc0;
+	};
+};
+
+&rtc0 {
+	status = "okay";
+};

tests/drivers/rtc/rtc_api/src/test_alarm.c

@@ -174,6 +174,9 @@ ZTEST(rtc_api, test_alarm)
 		}
 	}
 
+	/* Disable RTC IRQ, the irq will clear the alarm pending flag thus affects the test */
+	irq_disable(DT_IRQN(DT_ALIAS(rtc)));
+
 	for (uint8_t k = 0; k < 2; k++) {
 		/* Set RTC time */
 		ret = rtc_set_time(rtc, &test_rtc_time_set);
@@ -212,4 +215,7 @@ ZTEST(rtc_api, test_alarm)
 		ret = rtc_alarm_is_pending(rtc, i);
 		zassert_true(ret > -1, "Failed to clear alarm %d pending state", i);
 	}
+
+	/* Re-enable IRQ after test */
+	irq_enable(DT_IRQN(DT_ALIAS(rtc)));
 }