7938 Port ZOL #3712 disable LBA weighting on files and SSDs

@@ -151,10 +151,11 @@
         vdev_t          **vdev_child;   /* array of children            */
         uint64_t        vdev_children;  /* number of children           */
         vdev_stat_t     vdev_stat;      /* virtual device statistics    */
         boolean_t       vdev_expanding; /* expand the vdev?             */
         boolean_t       vdev_reopening; /* reopen in progress?          */
+        boolean_t       vdev_nonrot;    /* true if SSD, file, or Virtio */
         int             vdev_open_error; /* error on last open          */
         kthread_t       *vdev_open_thread; /* thread opening children   */
         uint64_t        vdev_crtxg;     /* txg when top-level was added */
 
         /*