x86, microcode, amd: Make find_ucode_in_initrd() __init

Change find_ucode_in_initrd() to __init and only let BSP call it
during cold boot. This is the right thing to do because only BSP will
see initrd loaded by the boot loader. APs will offset into
initrd_start to find the microcode patch binary.

Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Link: http://lkml.kernel.org/r/1370463236-2115-2-git-send-email-jacob.shin@amd.com


Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>