hostinfo,tailcfg: report TPM availability on windows/linux (#15831)

Start collecting fleet data on TPM availability via hostinfo.

Updates #15830

Signed-off-by: Andrew Lytvynov <awly@tailscale.com>

feature/tpm/tpm_other.go

@@ -0,0 +1,12 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build !linux && !windows
+
+package tpm
+
+import "tailscale.com/tailcfg"
+
+func info() *tailcfg.TPMInfo {
+	return nil
+}