time: ntp: simplify the second_overflow() code flow

Impact: cleanup, no functionality changed

Instead of a hierarchy of conditions, transform them to clean
gradual conditions and return's.

This makes the flow easier to read and makes the purpose of
the function easier to understand.

kernel/time/ntp.o:

   text	   data	    bss	    dec	    hex	filename
   2552	    170	    168	   2890	    b4a	ntp.o.before
   2552	    170	    168	   2890	    b4a	ntp.o.after

md5:
   eae1275df0b7d6290c13f6f6f8f05c8c  ntp.o.before.asm
   eae1275df0b7d6290c13f6f6f8f05c8c  ntp.o.after.asm
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kernel/time/ntp.c

@@ -232,19 +232,24 @@ void second_overflow(void)
 	time_offset	-= time_adj;
 	tick_length	+= time_adj;
 
-	if (unlikely(time_adjust)) {
-		if (time_adjust > MAX_TICKADJ) {
-			time_adjust -= MAX_TICKADJ;
-			tick_length += MAX_TICKADJ_SCALED;
-		} else if (time_adjust < -MAX_TICKADJ) {
-			time_adjust += MAX_TICKADJ;
-			tick_length -= MAX_TICKADJ_SCALED;
-		} else {
-			tick_length += (s64)(time_adjust * NSEC_PER_USEC /
-					NTP_INTERVAL_FREQ) << NTP_SCALE_SHIFT;
-			time_adjust = 0;
-		}
+	if (!time_adjust)
+		return;
+
+	if (time_adjust > MAX_TICKADJ) {
+		time_adjust -= MAX_TICKADJ;
+		tick_length += MAX_TICKADJ_SCALED;
+		return;
 	}
+
+	if (time_adjust < -MAX_TICKADJ) {
+		time_adjust += MAX_TICKADJ;
+		tick_length -= MAX_TICKADJ_SCALED;
+		return;
+	}
+
+	tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ)
+							 << NTP_SCALE_SHIFT;
+	time_adjust = 0;
 }
 
 #ifdef CONFIG_GENERIC_CMOS_UPDATE