Update sub-modules

sonic-snmpagent
7e46eb1 [201911][RFC1213]: Initialize lag oid map in reinit_data (#234)
aa98ded CPU Spike because of redundant and flooded keyspace notifis handled (#230)

sonic-swss
bc4e334 [Mux orch] Handle setting unknown mux state (#1984)
bd3630b [tunnel decap] Change tunnel orch order (#1977)
87a673a Fix the option missing in kernel config issue (#1973)
57967a1 [orchagent] Fix group name of port-buffer-drop in flexcounterorch.cpp (#1967)

sonic-utilities
181e8b0 Fix the option missing in kernel config issue (#1888)
21c0cc0 [watermarkstat] Fix for error in processing empty array from couters db (#1810)
7f15755 [chassis][supervisor][show][interfaces]show interfaces command warning on Supervisor card (#1771)