tpm: Tidy up use of size_t

tpm: Tidy up use of size_t

We should consistently use %z with size_t, and avoid passing a uint32_t as
a size_t value. Fix these issues to avoid warnings on 64-bit machines.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>