rawgpsd: add flag for cold start (#30224)

* rawgpsd: add flag for cold start

* other datasheet is wrong

* keep things in a good state

system/sensord/rawgps/rawgpsd.py

@@ -190,7 +190,13 @@ def setup_quectel(diag: ModemDiag) -> bool:
 
   if gps_enabled():
     at_cmd("AT+QGPSEND")
-  #at_cmd("AT+QGPSDEL=0")
+
+  if "GPS_COLD_START" in os.environ:
+    # deletes all assistance
+    at_cmd("AT+QGPSDEL=0")
+  else:
+    # allow module to perform hot start
+    at_cmd("AT+QGPSDEL=1")
 
   # disable DPO power savings for more accuracy
   at_cmd("AT+QGPSCFG=\"dpoenable\",0")