x86: remove boi handler support, eoi argument

This was only needed for the older 8259A style PICs which are no
longer supported.

Since we now just support APIC, we always just call loapic_eoi which
no longer requires an argument and informs the IOAPIC that the interrupt
is complete if necessary.

Change-Id: I15c9b7b4f03b872656220af32220b62e043bfa6b
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>