Simplify check whether a mdspan header file is available for inclusion

Author: dyniols

sycl/include/sycl/khr/group_interface.hpp

@@ -15,11 +15,9 @@
 #define SYCL_KHR_GROUP_INTERFACE 1
 #endif
 
-#if __cplusplus >= 202302L && defined(__has_include)
 #if __has_include(<mdspan>)
 #include <mdspan>
 #endif
-#endif
 
 namespace sycl {
 inline namespace _V1 {