rtc: cmos: Replace spin_lock_irqsave with spin_lock in hard IRQ

It is redundant to do irqsave and irqrestore in hardIRQ context, where
it has been in a irq-disabled context.

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/1612355981-6764-2-git-send-email-tanxiaofei@huawei.com

drivers/rtc/rtc-cmos.c

@@ -643,11 +643,10 @@ static struct cmos_rtc	cmos_rtc;
 
 static irqreturn_t cmos_interrupt(int irq, void *p)
 {
-	unsigned long	flags;
 	u8		irqstat;
 	u8		rtc_control;
 
-	spin_lock_irqsave(&rtc_lock, flags);
+	spin_lock(&rtc_lock);
 
 	/* When the HPET interrupt handler calls us, the interrupt
 	 * status is passed as arg1 instead of the irq number.  But
@@ -681,7 +680,7 @@ static irqreturn_t cmos_interrupt(int irq, void *p)
 			hpet_mask_rtc_irq_bit(RTC_AIE);
 		CMOS_READ(RTC_INTR_FLAGS);
 	}
-	spin_unlock_irqrestore(&rtc_lock, flags);
+	spin_unlock(&rtc_lock);
 
 	if (is_intr(irqstat)) {
 		rtc_update_irq(p, 1, irqstat);