x86: io-apic - do not use KERN_DEBUG marker too much

Do not use KERN_DEBUG several times on the same line being printed.
Introduced by mine previous patch, sorry.

Reported-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>