examples/vhost_crypto: remove unused short option

Short option "s" was passed to getopt_long function, while there was
no condition on this option.

Fixes: f518821 ("examples/vhost_crypto: add sample application")
Cc: stable@dpdk.org

Signed-off-by: Ibtisam Tariq <ibtisam.tariq@emumba.com>
Acked-by: Fan Zhang <roy.fan.zhang@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

examples/vhost_crypto/main.c

@@ -229,7 +229,7 @@ vhost_crypto_parse_args(int argc, char **argv)
 
 	argvopt = argv;
 
-	while ((opt = getopt_long(argc, argvopt, "s:",
+	while ((opt = getopt_long(argc, argvopt, "",
 				  lgopts, &option_index)) != EOF) {
 
 		if (opt == '?') {