gluon-core: make gluon.platform.match() match all boards when no boards are given

package/gluon-core/files/usr/lib/lua/gluon/platform.lua

@@ -21,7 +21,7 @@ function match(target, subtarget, boards)
       return false
    end
 
-   if not util.contains(boards, get_board_name()) then
+   if boards and not util.contains(boards, get_board_name()) then
       return false
    end