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>
diff --git a/drivers/rtc/rtc-tx4939.c b/drivers/rtc/rtc-tx4939.c
index 4f87234..2e678c6 100644
--- a/drivers/rtc/rtc-tx4939.c
+++ b/drivers/rtc/rtc-tx4939.c
@@ -176,8 +176,8 @@
 		tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_NOP);
 	}
 	spin_unlock(&pdata->lock);
-	if (likely(pdata->rtc))
-		rtc_update_irq(pdata->rtc, 1, events);
+	rtc_update_irq(pdata->rtc, 1, events);
+
 	return IRQ_HANDLED;
 }