i965: Fix instanced geometry shaders on Gen8+.
i965: Fix instanced geometry shaders on Gen8+.

Jordan added this in commit 741782b5948bb3d01d699f062a37513c2e73b076 for
Gen7 platforms.  I missed this when adding the Broadwell code.

Fixes Piglit's spec/arb_gpu_shader5/invocation-id-{basic,in-separate-gs}
with MESA_EXTENSION_OVERRIDE=GL_ARB_gpu_shader5 set.

Signed-off-by: Kenneth Graunke <bd2562f754ec92342f93f61c25d731e290a2ffa8@whitecape.org>
Reviewed-by: Jordan Justen <a79006884ba9cf5f4f7fcbb92a15b208780d8c97@intel.com>
Reviewed-by: Chris Forbes <5dcac483e7a6e31a5cbe89f38cc69dff8ee93dac@ijw.co.nz>
Cc: 59f39c0db42d4479a46b02d4d2bc11120e37bb44@lists.freedesktop.org

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler