Patch merged into coreboot/master: i2c/tpm: Ignore 0xFF bytes for status and burstCount

the following patch was just integrated into master:
commit a69ac7861b03e438e62c57992c30d9c42996c56b
Author: Julius Werner 
Date:   Wed Nov 30 17:46:17 2016 -0800

i2c/tpm: Ignore 0xFF bytes for status and burstCount

We've found that the SLB9645 TPM sometimes seems to randomly start
    returning 0xFF bytes for all requests. The exact cause is yet unknown,
    but we should try to write our TIS code such that it avoids bad
    interactions with this kind of response (e.g. any wait_for_status()
    immediately succeeds because all "status bits" are set in the response).
    At least for status and burstCount readings we can say for sure that the
    value is nonsensical and we're already reading those in a loop until we
    get valid results anyway, so let's add code to explicitly discount 0xFF
    bytes.

BRANCH=oak
    BUG=chrome-os-partner:55764
    TEST=None

Change-Id: I934d42c36d6847a22a185795cea49d282fa113d9
    Signed-off-by: Julius Werner 
    Reviewed-on: https://chromium-review.googlesource.com/420470
    Reviewed-by: Nicolas Boichat 
    Reviewed-on: https://review.coreboot.org/18006
    Tested-by: build bot (Jenkins)
    Reviewed-by: Martin Roth

See https://review.coreboot.org/18006 for details.

-gerrit