all: fix golangci-lint errors

These erroneously blocked a recent PR, which I fixed by simply
re-running CI. But we might as well fix them anyway.
These are mostly `printf` to `print` and a couple of `!=` to `!Equal()`

Updates #cleanup

Signed-off-by: Will Norris <will@tailscale.com>

cmd/tailscale/cli/risks.go

@@ -77,7 +77,7 @@ func presentRiskToUser(riskType, riskMessage, acceptedRisks string) error {
 	for left := riskAbortTimeSeconds; left > 0; left-- {
 		msg := fmt.Sprintf("\rContinuing in %d seconds...", left)
 		msgLen = len(msg)
-		printf(msg)
+		printf("%s", msg)
 		select {
 		case <-interrupt:
 			printf("\r%s\r", strings.Repeat("x", msgLen+1))