socket: Add time64 alias for sendmmsg

Reviewed-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

sysdeps/unix/sysv/linux/Versions

@@ -265,6 +265,7 @@ libc {
     __semctl64;
     __semtimedop64;
     __sem_timedwait64;
+    __sendmmsg64;
     __setitimer64;
     __settimeofday64;
     __shmctl64;