tpm: Add a 'tpm info' command

Add a command to display basic information about a TPM such as the model and
open/close state. This can be useful for debugging.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Christophe Ricard <christophe-h.ricard@st.com>
Reviewed-by: Heiko Schocher <hs@denx.de>