ilo: avoid brw_wm_barycentric_interp_mode in compiler

In preparation for replacing brw_defines.h.
ilo: add auto-generated headers

Add headers generated by http://github.com/olvaffe/envytools.
ilo: use auto-generated headers

Add genhw/genhw.h for inclusion by the rest of the driver.  The driver is
modified with a long sed script plus manual edits.
ilo: remove GPE command size estimation
ilo: remove GPE state size estimation
script