drivers/interrupt_controller/system_apic.c: remove dependence on IOAPIC

system_apic.c assumed that both a local APIC and I/O APIC are in use.
This caused compilation failures when the local APIC is enabled but no
I/O APIC is present (or configured). Fix preprocessor macros to allow
this configuration.

Signed-off-by: Charles E. Youse <charles.youse@intel.com>