Introduce generic TPM support in u-boot

Introduce generic TPM support in u-boot

TPM (Trusted Platform Module) is an integrated circuit and
software platform that provides computer manufacturers with the
core components of a subsystem used to assure authenticity,
integrity and confidentiality.

This driver supports version 1.2 of the TCG (Trusted Computing
Group) specifications.

The TCG specification defines several so called localities in a
TPM chip, to be controlled by different software layers. When
used on a typical x86 platform during the firmware phase, only
locality 0 can be accessed by the CPU, so this driver even while
supporting the locality concept presumes that only locality zero
is used.

This implementation is loosely based on the article "Writing a
TPM Device Driver" published on http://ptgmedia.pearsoncmg.com

Compiling this driver with DEBUG defined will generate trace of
all accesses to TMP registers.

This driver has been tested and is being used in three different
functional ChromeOS machines (Pinetrail and Sandy Bridge Intel
chipsets) all using the same Infineon SLB 9635 TT 1.2 device.

A u-boot cli command allowing access to the TPM was also
implemented and is being submitted as a second patch.

Change-Id: I22a33c3e5b2e20eec9557a7621bd463b30389d73
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
CC: Wolfgang Denk <wd@denx.de>