[coreboot] Patch merged into coreboot/master: 044489f xchg is atomic with side-effects

the following patch was just integrated into master:
commit 044489fc6f8e15eaafa4172186ec6a6fb79b4f90
Author: Patrick Georgi 
Date:   Sun Mar 11 19:42:33 2012 +0100

xchg is atomic with side-effects

clang doesn't know about the side effect, so we have to tell it
    that it's okay not to care about the result.

Change-Id: Ib11890bff6779e36cf09c178d224695ea16a8ae8
    Signed-off-by: Patrick Georgi

See http://review.coreboot.org/783 for details.

-gerrit