x86, microcode, amd: Fix missing static declaration

Make locally used variable static.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Link: http://lkml.kernel.org/r/1406146251-8540-1-git-send-email-hmh@hmh.eng.br


Signed-off-by: Borislav Petkov <bp@suse.de>