x86/microcode: Decrease CPUID use

Get CPUID(1).EAX value once per CPU and propagate value into the callers
instead of conveniently calling it every time.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-9-bp@alien8.de


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>