rtc: m41t80: do not use rtc_valid_tm in m41t80_rtc_read_alarm

Commit b485fe5 ("rtc/m41t80: use rtc_valid_tm() to check returned tm")
added rtc_valid_tm to m41t80_rtc_read_alarm() but it was wrong while the
t->time does not contain complete date/time.

This patch also fixes a warning:
warning: passing argument 1 of 'rtc_valid_tm' from incompatible pointer type

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-m41t80.c

@@ -364,7 +364,7 @@ static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 	t->time.tm_isdst = -1;
 	t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE);
 	t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF);
-	return rtc_valid_tm(t);
+	return 0;
 }
 
 static struct rtc_class_ops m41t80_rtc_ops = {