x86: apic - use pr_ macros for logging

Impact: cleanup

It saves us some source lines and shift the code a bit righter.

And a multiline comment style is fixed too :-)
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Acked-by: "Maciej W. Rozycki" <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>