consensus: log private validator address and not struct (#6144)

ref: https://github.com/tendermint/tendermint/pull/6140#discussion_r578635756

consensus/state.go

@@ -1095,7 +1095,6 @@ func (cs *State) enterPropose(height int64, round int32) {
 		logger.Debug(
 			"propose step; our turn to propose",
 			"proposer", address,
-			"priv_validator", cs.privValidator,
 		)
 
 		cs.decideProposal(height, round)
@@ -1103,7 +1102,6 @@ func (cs *State) enterPropose(height int64, round int32) {
 		logger.Debug(
 			"propose step; not our turn to propose",
 			"proposer", cs.Validators.GetProposer().Address,
-			"priv_validator", cs.privValidator,
 		)
 	}
 }