cansequence: main(): error handling: add "()" to function name in error message

Commit 0be066bee6 ("cansequence: main(): allow to bind on "any"
interface") converted from SIOCGIFINDEX ioctl() to if_nametoindex()
and adjusted the error message, but forgot the "()" after the function
name, which is used in the rest of the error messages in this file.

Add the missing "()".

Fixes: 0be066bee6 ("cansequence: main(): allow to bind on "any" interface")

cansequence.c

@@ -347,7 +347,7 @@ int main(int argc, char **argv)
 	if (strcmp(ANYDEV, interface)) {
 		addr.can_ifindex = if_nametoindex(interface);
 		if (!addr.can_ifindex) {
-			perror("if_nametoindex");
+			perror("if_nametoindex()");
 			exit(EXIT_FAILURE);
 		}
 	}