[flang][cuda] Add on_device interface to cudadevice (#134747)

Author: clementval

flang/module/cudadevice.f90

@@ -1609,4 +1609,9 @@ attributes(device) integer function ballot_sync(mask, pred)
     end subroutine
   end interface
 
+  interface
+    attributes(device,host) logical function on_device() bind(c)
+    end function
+  end interface
+
 end module