drm/i915/perf: Use GTT when saving/restoring engine GPR

drm/i915/perf: Use GTT when saving/restoring engine GPR

MI_STORE_REGISTER_MEM and MI_LOAD_REGISTER_MEM need to know which
translation to use when saving restoring the engine general purpose
registers to and from the GT scratch. Since GT scratch is mapped to
ggtt, we need to set an additional bit in the command to use GTT.

Fixes: daed3e44396d17 ("drm/i915/perf: implement active wait for noa configurations")
Suggested-by: Prathap Kumar Valsan <prathap.kumar.valsan@intel.com>
Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200709224504.11345-1-chris@chris-wilson.co.uk
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>