clover/util: Pass initial count value to ref_counter constructor.

And mark the ref_count() method as const.

Tested-by: EdB <edb+mesa@sigluy.net>

src/gallium/state_trackers/clover/util/pointer.hpp

@@ -31,10 +31,10 @@ namespace clover {
    ///
    class ref_counter {
    public:
-      ref_counter() : _ref_count(1) {}
+      ref_counter(unsigned value = 1) : _ref_count(value) {}
 
       unsigned
-      ref_count() {
+      ref_count() const {
          return _ref_count;
       }