clockevents: Prevent shift out of bounds

Andrey reported that on a kernel with UBSan enabled he found:

     UBSan: Undefined behaviour in ../kernel/time/clockevents.c:75:34

     I guess it should be 1ULL here instead of 1U:
            (!ismax || evt->mult <= (1U << evt->shift)))

That's indeed the correct solution because shift might be 32.

Reported-by: Andrey Ryabinin <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>

kernel/time/clockevents.c

@@ -72,7 +72,7 @@ static u64 cev_delta2ns(unsigned long latch, struct clock_event_device *evt,
 	 * Also omit the add if it would overflow the u64 boundary.
 	 */
 	if ((~0ULL - clc > rnd) &&
-	    (!ismax || evt->mult <= (1U << evt->shift)))
+	    (!ismax || evt->mult <= (1ULL << evt->shift)))
 		clc += rnd;
 
 	do_div(clc, evt->mult);