rtc: loongson: clear TOY_MATCH0_REG in loongson_rtc_isr()

The TOY_MATCH0_REG should be cleared to 0 in the RTC interrupt handler,
otherwise the interrupt cannot be cleared, which will cause the
loongson_rtc_isr() to be triggered multiple times.

The previous code cleared TOY_MATCH0_REG in the loongson_rtc_handler(),
which is an ACPI interrupt. This did not prevent loongson_rtc_isr()
from being triggered multiple times.

This commit moves the clearing of TOY_MATCH0_REG to the
loongson_rtc_isr() to ensure that the interrupt is properly cleared.

Fixes: 1b733a9ebc3d ("rtc: Add rtc driver for the Loongson family chips")
Signed-off-by: Ming Wang <[e-mail]>
Reviewed-by: Huacai Chen <[e-mail]>
Reviewed-by: Keguang Zhang <[e-mail]> # on LS1B
Tested-by: Keguang Zhang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexandre Belloni <[e-mail]>

drivers/rtc/rtc-loongson.c

···
 	struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
 
 	rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
+
+	/*
+	 * The TOY_MATCH0_REG should be cleared 0 here,
+	 * otherwise the interrupt cannot be cleared.
+	 */
+	regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
+
 	return IRQ_HANDLED;
 }
 
···
 	writel(RTC_STS, priv->pm_base + PM1_STS_REG);
 	spin_unlock(&priv->lock);
 
-	/*
-	 * The TOY_MATCH0_REG should be cleared 0 here,
-	 * otherwise the interrupt cannot be cleared.
-	 */
-	return regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
+	return ACPI_INTERRUPT_HANDLED;
 }
 
 static int loongson_rtc_set_enabled(struct device *dev)