x86, microcode_intel_early: Mark apply_microcode_early() as cpuinit

Add missing __cpuinit annotation to apply_microcode_early().

Reported-by: Shaun Ruffell <sruffell@digium.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/20130320170310.GA23362@digium.com


Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>