x86, amd, microcode: Fix error path in apply_microcode_amd()

Return -1 (like Intels apply_microcode) when the loading fails, also
do not set the active microcode level on failure.

Signed-off-by: Torsten Kaiser <just.for.lkml@googlemail.com>
Link: http://lkml.kernel.org/r/20130723225823.2e4e7588@googlemail.com


Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>