APIC MMIO reads/writes use the helper

Some of the operations (like the IOAPIC version read) were getting
optimized such that they didn't work properly.  Like reading a byte
instead of the entire aligned 32 bit IOAPIC version.
x86: irq asm handlers for non-PIC irqs

The APICS (IO, etc) can generate vectors beyond 47, so we need
IRQ_HANDLER stubs for them.

This was actually a fun commit: vim macro and CTRL-A to increment.