Eina promise: Simplify code and remove shadow variable.

There was no need for the extra variable. This also fixes a shadow
warning.

src/lib/eina/eina_promise.c

@@ -280,8 +280,7 @@ _eina_promise_pointer_value_get(_Eina_Promise_Default const* p)
    if (p->has_finished && !p->has_errored)
      {
         char const* buffer = promise->value;
-        void** p = (void**)buffer;
-        return *p;
+        return (void**)buffer;
      }
    else
      {