[dualtor] Fix mux start failure due to pre operation timeout (sonic-net#22027)

[dualtor] Fix `mux` start failure due to pre operation timeout

Author: mssonicbld

files/build_templates/mux.service.j2

@@ -8,6 +8,7 @@ StartLimitIntervalSec=1200
 StartLimitBurst=3
 
 [Service]
+TimeoutStartSec=180
 User={{ sonicadmin_user }}
 ExecStartPre=/usr/local/bin/write_standby.py
 ExecStartPre=/usr/local/bin/mark_dhcp_packet.py

files/scripts/write_standby.py

@@ -136,7 +136,7 @@ def tunnel_exists(self):
         tunnel_key_pattern = 'ASIC_STATE:SAI_OBJECT_TYPE_TUNNEL:*'
         return len(self.asic_db.keys('ASIC_DB', tunnel_key_pattern)) > 0
 
-    def wait_for_tunnel(self, interval=1, timeout=90):
+    def wait_for_tunnel(self, interval=1, timeout=160):
         """
         Waits until the IP-in-IP tunnel has been created