tpm: refactor function names for LPC based TPMs

With the upcoming TPM2 API, some of the functions name are part of the new
header file.  So switch conflicting internal function names and defines.

Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canaonical.com>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>