net: dhcp: Fix return value on ctrl-c

the dhcp command will return with 0 when ctrl-c is pressed. Fix this to
-EINTR instead.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/dhcp.c

@@ -767,8 +767,10 @@ static int do_dhcp(int argc, char *argv[])
 		goto out1;
 
 	while (dhcp_state != BOUND) {
-		if (ctrlc())
-			break;
+		if (ctrlc()) {
+			ret = -EINTR;
+			goto out1;
+		}
 		if (!retries) {
 			ret = -ETIMEDOUT;
 			goto out1;