fix tiny leak

kernel/storedev/storedev.c

@@ -135,6 +135,7 @@ StoreDev *storedev_create(int32_t sdtype, char *name, void *extra) {
       sd->sectorsize = 0; // lazy
     } break;
     default:
+      dlfree(sd);
       spinlock_release(&STOREDEV_LIST.spinlock);
       return NULL;
   }