add Hyundai CAN FD fingerprinting note

selfdrive/car/hyundai/values.py

@@ -648,6 +648,8 @@ PLATFORM_CODE_ECUS = [Ecu.fwdRadar, Ecu.fwdCamera, Ecu.eps]
 # TODO: there are date codes in the ABS firmware versions in hex
 DATE_FW_ECUS = [Ecu.fwdCamera]
 
+# Note: an ECU on CAN FD cars may sometimes send 0x30080aaaaaaaaaaa (flow control continue) while we
+# are attempting to query ECUs. This currently does not seem to affect fingerprinting from the camera
 FW_QUERY_CONFIG = FwQueryConfig(
   requests=[
     # TODO: add back whitelists