transport: fix LOG_DEBUG gaffe

LOG_DEBUG() arguments are only evaluated when DEBUG logging
is enabled, do not use arguments that have side effects
like foo++.
Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>

src/jtag/transport.c

@@ -125,8 +125,10 @@ int allow_transports(struct command_context *ctx, const char **vector)
 	} else {
 		/* guard against user config errors */
 		LOG_WARNING("must select a transport.");
-		while (*vector)
-			LOG_DEBUG("allow transport '%s'", *vector++);
+		while (*vector) {
+			LOG_DEBUG("allow transport '%s'", *vector);
+			vector++;
+		}
 		return ERROR_OK;
 	}
 }