selftests/net: so_txtime: fix parsing of start time stamp on 32 bit systems

This patch fixes the parsing of the cmd line supplied start time on 32
bit systems. A "long" on 32 bit systems is only 32 bit wide and cannot
hold a timestamp in nano second resolution.

Fixes: 04080634 ("selftests/net: so_txtime multi-host support")
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20220502094638.1921702-2-mkl@pengutronix.deSigned-off-by: Paolo Abeni <pabeni@redhat.com>

tools/testing/selftests/net/so_txtime.c

@@ -475,7 +475,7 @@ static void parse_opts(int argc, char **argv)
 			cfg_rx = true;
 			break;
 		case 't':
-			cfg_start_time_ns = strtol(optarg, NULL, 0);
+			cfg_start_time_ns = strtoll(optarg, NULL, 0);
 			break;
 		case 'm':
 			cfg_mark = strtol(optarg, NULL, 0);