Avoid returning void

It's silly and non-conforming to standards to return void,
don't do it.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/block.c b/block.c
index ce7eb8f..b38940b 100644
--- a/block.c
+++ b/block.c
@@ -2609,7 +2609,7 @@
         return;
     }
 
-    return drv->bdrv_debug_event(bs, event);
+    drv->bdrv_debug_event(bs, event);
 
 }