i965/inst: Add gateway_notify and gateway_subfuncid fields
i965/inst: Add gateway_notify and gateway_subfuncid fields

These fields will be used when emitting a send for the barrier function.

Reference: IVB PRM Volume 4, Part 2, Section 1.1.1 Message Descriptor

v2:
 * notify => gateway_notify (Ken)
 * define bits for gen4-gen6 (bwidawsk, Ken)

Signed-off-by: Jordan Justen <a79006884ba9cf5f4f7fcbb92a15b208780d8c97@intel.com>
Reviewed-by: Chris Forbes <5dcac483e7a6e31a5cbe89f38cc69dff8ee93dac@ijw.co.nz>
Reviewed-by: Ben Widawsky <73675debcd8a436be48ec22211dcf44fe0df0a64@bwidawsk.net>
Reviewed-by: Kenneth Graunke <bd2562f754ec92342f93f61c25d731e290a2ffa8@whitecape.org>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler