Removing acpi.ko support

[John Baldwin]

[ cc'ing acpi@ to be safe, but I think the topic warrants the wider audience 
of arch@ ]

I think we should drop support for having acpi load as a module for i386.  It 
adds extra complication and hacks to the i386 APIC and interrupt code that are 
gratuitously different from amd64 as a result.  Originally it was made a 
module so that GENERIC on i386 did not include ACPI by default but would only 
use up memory to hold ACPI-related code if the machine supported ACPI.  Now 
that acpi is part of GENERIC on i386 in 8.0 and later this argument is no 
longer relevant.  I'd like to remove support for ACPI as a module to remove 
the various hacks on i386 and reduce differences with amd64.

-- 
John Baldwin