tpm: Don't include cr50 in TPL/SPL

At present the security chip is not used in these U-Boot phases. Update
the Makefile to exclude it.

Fix a few logging statements while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>