Add missing return, in a rare case where we can't allocate memory in

deallocate.

Submitted by:	Ryan Stone (rysto32 at gmail dot com)
Approved by:	jasone

lib/libc/stdlib/malloc.c

@@ -3800,6 +3800,7 @@ arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr)
 					arena_dalloc_small(arena, chunk, ptr,
 					    mapelm);
 					malloc_spin_unlock(&arena->lock);
+					return;
 				}
 				mag_rack = rack;
 			}