remove duplicate addresses from firmware query. Fixes #1088 (#1100)

* remove duplicate addresses from firmware query

* Update release notes

RELEASES.md

@@ -2,6 +2,7 @@ Version 0.7.3 (2020-xx-xx)
 ========================
  * Support for 2020 Highlander thanks to che220!
  * Support for 2018 Lexus NX 300h thanks to kengggg!
+ * Speed up ECU firmware query
 
 Version 0.7.2 (2020-02-07)
 ========================

selfdrive/car/fw_versions.py

@@ -123,9 +123,12 @@ def get_fw_versions(logcan, sendcan, bus, extra=None, timeout=0.1, debug=False,
         ecu_types[a] = ecu_type
 
       if sub_addr is None:
-        parallel_addrs.append(a)
+        if a not in parallel_addrs:
+          parallel_addrs.append(a)
       else:
-        addrs.append([a])
+        if [a] not in addrs:
+          addrs.append([a])
+
   addrs.insert(0, parallel_addrs)
 
   fw_versions = {}