[PKT_SCHED]: Fix range in PSCHED_TDIFF_SAFE to 0..bound

Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/pkt_sched.h

@@ -157,7 +157,8 @@ psched_tod_diff(int delta_sec, int bound)
 	   case 1: \
 		   __delta += 1000000; \
 	   case 0: \
-		   __delta = abs(__delta); \
+ 		   if (__delta > bound || __delta < 0) \
+ 			__delta = bound; \
 	   } \
 	   __delta; \
 })