[DeviceSanitizer][NFC] Remove unnecessary warning for asan libdevice (intel#18049)

The latest asan libdevice source triggers a compiler warning:
llvm/libdevice/sanitizer/asan_rtl.cpp:342:3: warning: label at end of
compound statement is a C++23 extension [-Wc++23-extensions]
This trivial pr removes it.

Signed-off-by: jinge90 <ge.jin@intel.com>

Author: jinge90

libdevice/sanitizer/asan_rtl.cpp

@@ -339,6 +339,7 @@ void __asan_exit(ErrorType error_type) {
     __devicelib_exit();
     break;
   default:
+    break;
   }
 }