[SYCL] Implement decorated enum class (#5399)

Added enum class sycl::access::decorated to access.hpp, so it would be possible to perform tests demanding this implementation.

Author: IgorKharchikov

sycl/include/CL/sycl/access/access.hpp

@@ -58,6 +58,7 @@ enum class address_space : int {
   generic_space = 6, // TODO generic_space address space is not supported yet
 };
 
+enum class decorated : int { no = 0, yes = 1, legacy = 2 };
 } // namespace access
 
 using access::target;