[DM/FIXUP] Fixup block ref_count check in unregister

ref_count should zero in unregister.

Signed-off-by: GuEe-GUI <[email protected]>

components/drivers/block/blk.c

@@ -344,7 +344,7 @@ rt_err_t rt_hw_blk_disk_unregister(struct rt_blk_disk *disk)
 
     spin_lock(&disk->lock);
 
-    if (disk->parent.ref_count != 1)
+    if (disk->parent.ref_count > 0)
     {
         err = -RT_EBUSY;
         goto _unlock;