mei: simplify io callback disposal

Simplify disposal of io callback by removing the callback
implicitly from its lookup list inside mei_io_cb_free

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
index 2c581dc..58da925 100644
--- a/drivers/misc/mei/hbm.c
+++ b/drivers/misc/mei/hbm.c
@@ -639,7 +639,7 @@
 			continue;
 
 		if (mei_hbm_cl_addr_equal(cl, rs)) {
-			list_del(&cb->list);
+			list_del_init(&cb->list);
 			break;
 		}
 	}