drm/i915/selftest: Fix MOCS selftest for GuC submission

drm/i915/selftest: Fix MOCS selftest for GuC submission

When GuC submission is enabled, the GuC controls engine resets. Rather
than explicitly triggering a reset, the driver must submit a hanging
context to GuC and wait for the reset to occur.

Signed-off-by: Rahul Kumar Singh <rahul.kumar.singh@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210727002348.97202-29-matthew.brost@intel.com