i915: Remove IS_9XX macro

Since the i915 / i965 split, IS_9XX just means IS_GEN3.  Inspired by
Damien's recent libdrm changes.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
2 files changed