Set uninitialized popmap bits in vm_reserv_init

In vm_reserv_init, set all the marker popmap bits in vm_reserv_init,
and not just the bits of the first popmap entry.

Reviewed by:	markj
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D33258

sys/vm/vm_reserv.c

@@ -1112,7 +1112,7 @@ vm_reserv_init(void)
 		 * partially populated reservation queues.
 		 */
 		rvd->marker.popcnt = VM_LEVEL_0_NPAGES;
-		for (j = 0; j < NBPOPMAP; j++)
+		for (j = 0; j < VM_LEVEL_0_NPAGES; j++)
 			popmap_set(rvd->marker.popmap, j);
 	}