vcu118-run.py: Don't depend on endpoint iteration order for TTY

The documentation explicitly states there is no order, so make sure we
pick up the right TTY from the dual port UART. On tiger this seems to be
getting them backwards.

vcu118-run.py

@@ -440,13 +440,19 @@ def find_vcu118_tty(pretend: bool) -> ListPortInfo:
     # find the serial port:
     expected_vendor_id = 0x10C4
     expected_product_id = 0xEA70
+    expected_endpoint = ":1.1"
     for portinfo in comports(include_links=True):
         assert isinstance(portinfo, ListPortInfo)
-        if portinfo.pid == expected_product_id and portinfo.vid == expected_vendor_id:
+        if (
+            portinfo.pid == expected_product_id
+            and portinfo.vid == expected_vendor_id
+            and portinfo.location.endswith(expected_endpoint)
+        ):
             return portinfo
     if pretend:
         return ListPortInfo("/dev/fakeTTY")
-    raise ValueError("Could not find USB TTY with VID", hex(expected_vendor_id), "PID", hex(expected_product_id))
+    raise ValueError("Could not find USB TTY with VID", hex(expected_vendor_id), "PID", hex(expected_product_id),
+                     "endpoint", expected_endpoint)
 
 
 def main():