Patch merged into coreboot/master: 125a6a2 libpayload: Add a timer_us() function.

the following patch was just integrated into master:
commit 125a6a22f81b3cf11732ce2a0e77652661fa0764
Author: Gabe Black 
Date:   Fri Dec 6 23:30:10 2013 -0800

libpayload: Add a timer_us() function.

This function returns the number of microseconds scaled from the number of raw
    timer ticks. It accepts a base parameter which is subtracted from the current
    time, which makes it easy to keep track of relative times.

Change-Id: I55f2f9e90c0e12cda430bbe88b044f12b0b563c8
    Signed-off-by: Gabe Black 
    Reviewed-on: https://chromium-review.googlesource.com/179600
    Reviewed-by: Ronald Minnich 
    Commit-Queue: Gabe Black 
    Tested-by: Gabe Black 
    (cherry picked from commit 4dd549e18d170dbf918c5b4b11bbe1f4e99b6695)
    Signed-off-by: Isaac Christensen 
    Reviewed-on: http://review.coreboot.org/6897
    Tested-by: build bot (Jenkins)
    Reviewed-by: Ronald G. Minnich

See http://review.coreboot.org/6897 for details.

-gerrit