x86_64: Move apic calibration code around

Let the calibration code fill in calibration_result directly and
move the variable on top of the file.

Fixup a printk w/o log level while at it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>