ilo: use only defines from genhw headers

Stop including classic driver headers in genhw.h, with some formatting fixes.
ilo: remove unused headers

Remove intel_*.h.  brw_*.h is still needed by the state dumper and
disassembler.
ilo: remove GPE command size estimation

Use size defines from genhw.
ilo: remove GPE state size estimation

Use size defines from genhw.