x86: move {un}map_cpu_to_logical_apicid to smpboot.c

Move map_cpu_to_logical_apicid() and unmap_cpu_to_logical_apicid()
to smpboot.c. They take together all the bunch of static functions
they rely upon

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>