drm/i915: Add opt_acpi.h and acpi_if.h to the source files

While here, sort the list of generated source files.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@270571 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
drm/i915: Disable the build of i915 on PC98

This module is of no use on this platform and now, i915 depends on ACPI
anyway.

Suggested by:	nyan@


git-svn-id: svn+ssh://svn.freebsd.org/base/head@270572 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f