gfxmenu: Remove trailing whitespaces

Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

grub-core/gfxmenu/gui_circular_progress.c

@@ -220,7 +220,7 @@ static void
 circprog_set_state (void *vself, int visible, int start,
 		    int current, int end)
 {
-  circular_progress_t self = vself;  
+  circular_progress_t self = vself;
   self->visible = visible;
   self->start = start;
   self->value = current;