rtc: treewide: remove excess rtc_device validation

The patch "rtc: verify a critical argument to rtc_update_irq() before
using it" introduces validation for rtc_device in the RTC core, so there
are no need to check this argument for rtc_update_irq() from the
drivers.

This patch removes such check for the existing rtc_update_irq() users.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-ds1511.c

@@ -371,7 +371,6 @@ ds1511_interrupt(int irq, void *dev_id)
 			events |= RTC_UF;
 		else
 			events |= RTC_AF;
-		if (likely(pdata->rtc))
 		rtc_update_irq(pdata->rtc, 1, events);
 	}
 	spin_unlock(&pdata->lock);

drivers/rtc/rtc-ds1553.c

@@ -206,7 +206,6 @@ static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)
 			events |= RTC_UF;
 		else
 			events |= RTC_AF;
-		if (likely(pdata->rtc))
 		rtc_update_irq(pdata->rtc, 1, events);
 	}
 	spin_unlock(&pdata->lock);

drivers/rtc/rtc-stk17ta8.c

@@ -214,7 +214,6 @@ static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id)
 			events |= RTC_UF;
 		else
 			events |= RTC_AF;
-		if (likely(pdata->rtc))
 		rtc_update_irq(pdata->rtc, 1, events);
 	}
 	spin_unlock(&pdata->lock);

drivers/rtc/rtc-tx4939.c

@@ -176,8 +176,8 @@ static irqreturn_t tx4939_rtc_interrupt(int irq, void *dev_id)
 		tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_NOP);
 	}
 	spin_unlock(&pdata->lock);
-	if (likely(pdata->rtc))
 	rtc_update_irq(pdata->rtc, 1, events);
+
 	return IRQ_HANDLED;
 }