x86/cpu: Get rid of compute_unit_id

It is cpu_core_id anyway.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1458917557-8757-3-git-send-email-bp@alien8.de


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