drivers/i2c/tpm: Split cr50 driver from main driver

Originally I thought it would be cleaner to keep this code in one
place, but as things continue to diverge it ends up being easier
to split this into its own driver.  This way the different drivers
in coreboot, depthcharge, and the kernel, can all be standalone
and if one is changed it is easier to modify the others.

This change splits out the cr50 driver and brings along the basic
elements from the existing driver with no real change in
functionality.  The following commits will modify the code to make
it consistent so it can all be shared with depthcharge and the
linux kernel drivers.

BUG=chrome-os-partner:53336

Change-Id: I3b62b680773d23cc5a7d2217b9754c6c28bccfa7
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://review.coreboot.org/16663
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
4 files changed