Kernel: Fix -Wunreachable-code warnings from clang

Author: https://github.com/nico
Commit: 1cdb12e920
Pull-request: https://github.com/SerenityOS/serenity/pull/10399

Kernel/Net/LocalSocket.cpp

@@ -413,7 +413,7 @@ KResult LocalSocket::getsockopt(OpenFileDescription& description, int level, int
         default:
             return EINVAL;
         }
-        break;
+        VERIFY_NOT_REACHED();
     }
     default:
         return Socket::getsockopt(description, level, option, value, value_size);