[flashrom] Patch to fix wrmsr for some toolchains

[Mart Raudsepp]

Hello,

My co-worker sent me a patch many months ago to forward upstream as
appropriate, but apparently I had forgotten to do so and now hit the bug
with my compiler version as well while testing something from SVN.

So attached is that patch now, so that flash chip detection would work
again on my Geode/CS5536 system.

PS: I'm not subscribed to flashrom list right now, so please CC me on
any replies

Regards,
Mart Raudsepp