Apply constexpr on global constant varaibles

When HIP_ENABLE_DEFERRED_LOADING=0, many global variables will be
referenced but they are not initialized in that early time. The patch
will use constexpr to initialze global constant varables in compile
time.

Change-Id: I9d538b7abc6a0ce700ec3332b97fc144db5fc1ef

rocclr/utils/concurrent.hpp

@@ -34,7 +34,7 @@ namespace amd { /*@{*/
 namespace details {
 
 template <typename T, int N> struct TaggedPointerHelper {
-  static const uintptr_t TagMask = (1u << N) - 1;
+  static constexpr uintptr_t TagMask = (1u << N) - 1;
 
  private:
   TaggedPointerHelper();        // Cannot instantiate