Patch merged into coreboot/master: 1c5cdad libpayload: improve us timer accuracy

the following patch was just integrated into master:
commit 1c5cdad09efa7d6bd196ad852dbeb5f740ac66e3
Author: Vadim Bendebury 
Date:   Thu Jul 10 12:49:46 2014 -0700

libpayload: improve us timer accuracy

In cases where timer clock frequency is not an integer number of
    megahertz, the calculations in timer_us() lack accuracy.

This patch modifies calculations to reduce the error. The maximum
    interval this calculation would support decreases, but it still is in
    excess of 1844674 seconds for a timer clocked by 10 MHz, which is more
    than enough.

BUG=none
    TEST=manual
      . verified timer accuracy using a depthcharge CLI command

Original-Change-Id: Iffb323db10e74b0ce3b4d59a56983bfee12e6805
    Original-Signed-off-by: Vadim Bendebury 
    Original-Reviewed-on: https://chromium-review.googlesource.com/207358
    Original-Reviewed-by: David Hendricks 
    (cherry picked from commit e1abf87d438de1a04714482d5b610671e8cc0663)
    Signed-off-by: Marc Jones

Change-Id: Ia892726187ab040dd235f493c92856c15951cc06
    Reviewed-on: http://review.coreboot.org/8128
    Reviewed-by: Stefan Reinauer 
    Reviewed-by: Paul Menzel 
    Tested-by: build bot (Jenkins)

See http://review.coreboot.org/8128 for details.

-gerrit