[neighsyncd] increase neighsyncd timeout (sonic-net#2209)

- What I did
Increased the neighsyncd timeout.

- Why I did it
Restore_neigh takes a bit more time to start thus it could be that the neighsyncd timeout is not enough to wait for restore_neighbors

- How I verified it
py.test platform_tests/test_advanced_reboot.py::test_warm_reboot_sad[sad_lag_member] --inventory="../ansible/inventory,../ansible/veos" --host-pattern arc-switch1004 --module-path ../ansible/library/ --testbed arc-switch1004-t0-56 --testbed_file ../ansible/testbed.csv --allow_recover --log-cli-level info --skip_sanity

Signed-off-by: Stepan Blyschak <stepanb@nvidia.com>

neighsyncd/neighsync.h

@@ -14,7 +14,7 @@
  * service to finish, should be longer than the restore_neighbors timeout value (110)
  * This should not happen, if happens, system is in a unknown state, we should exit.
  */
-#define RESTORE_NEIGH_WAIT_TIME_OUT 120
+#define RESTORE_NEIGH_WAIT_TIME_OUT 180
 
 namespace swss {