[mutter/pwood/fix-trackball-button-scroll] meta-input-settings: fix device list iteration

[Phillip Wood <pwood src gnome org>]

commit adbc7ef915d6286e24af9acd30a0b9fd4f7a5f6c
Author: Phillip Wood <phillip wood dunelm org uk>
Date:   Sat Apr 11 16:08:18 2020 +0100

    meta-input-settings: fix device list iteration
    
    Dereference the loop variable rather than the original list head. This
    fixes a regression introduced in 4413b86a3 ("backends: Replace
    ClutterDeviceManager usage in favor of ClutterSeat", 2019-10-04) which
    broke button scrolling with trackballs.
    
    Closes:https://gitlab.gnome.org/GNOME/mutter/-/issues/1120

 src/backends/meta-input-settings.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/backends/meta-input-settings.c b/src/backends/meta-input-settings.c
index 2028570c0..5b2cee29f 100644
--- a/src/backends/meta-input-settings.c
+++ b/src/backends/meta-input-settings.c
@@ -818,7 +818,7 @@ update_trackball_scroll_button (MetaInputSettings  *input_settings,
 
       for (l = devices; l; l = l->next)
         {
-          device = devices->data;
+          device = l->data;
 
           if (input_settings_class->is_trackball_device (input_settings, device))
             input_settings_class->set_scroll_button (input_settings, device, button);