sched: fix calc_delta_mine()

lw->weight can be 0 for a short time during bootup.

Signed-off-by: Ingo Molnar <[e-mail]>
Signed-off-by: Peter Zijlstra <[e-mail]>

kernel/sched.c

···
 	u64 tmp;
 
 	if (unlikely(!lw->inv_weight))
-		lw->inv_weight = (WMULT_CONST - lw->weight/2) / lw->weight + 1;
+		lw->inv_weight = (WMULT_CONST-lw->weight/2) / (lw->weight+1);
 
 	tmp = (u64)delta_exec * weight;
 	/*