Revert "linux(4): The futex_wait operation should restart."

This reverts commit 5eec19c8eb due to its
wrong. Linux interrupts futex syscall on signal and return EINTR.

sys/compat/linux/linux_futex.c

@@ -786,6 +786,8 @@ linux_futex_wait(struct thread *td, struct linux_futex_args *args)
 	}
 	umtxq_unlock(&uq->uq_key);
 	umtx_key_release(&uq->uq_key);
+	if (error == ERESTART)
+		error = EINTR;
 	return (error);
 }