Return the correct value from calc_latency()

Some stray sector_t's -> unsigned long long
--- diff/drivers/md/dm-iostats.c	2002-12-17 15:35:30.000000000 +0000
+++ source/drivers/md/dm-iostats.c	2002-12-17 15:36:59.000000000 +0000
@@ -138,7 +138,8 @@
 static void div64(unsigned long long a, unsigned long long b,
 		  unsigned long long *n)
 {
-	sector_t acc, prev, i;
+	unsigned int i;
+	unsigned long long acc, prev;
 
 	*n = 0;
 	while (a >= b) {
@@ -170,7 +171,7 @@
 	latency *= 1000;
 	latency /= HZ;
 
-	return (unsigned long) delta;
+	return latency;
 }
 
 static int iostats_status(struct dm_target *ti, status_type_t type,