drm/i915/gem: Consider multi-gt instead of to_gt()

In order to enable complete multi-GT, use the GT
reference obtained directly from the engine, rather
than relying on the to_gt(), which only provides a
reference to the primary GT.

Problem appear when it runs on platform like MTL
where different set of engines are possible on
different GTs.
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230419060036.3422635-3-tejas.upadhyay@intel.com

drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c

@@ -93,7 +93,7 @@ static int live_nop_switch(void *arg)
 		}
 		if (i915_request_wait(rq, 0, 10 * HZ) < 0) {
 			pr_err("Failed to populated %d contexts\n", nctx);
-			intel_gt_set_wedged(to_gt(i915));
+			intel_gt_set_wedged(engine->gt);
 			i915_request_put(rq);
 			err = -EIO;
 			goto out_file;
@@ -149,7 +149,7 @@ static int live_nop_switch(void *arg)
 			if (i915_request_wait(rq, 0, HZ / 5) < 0) {
 				pr_err("Switching between %ld contexts timed out\n",
 				       prime);
-				intel_gt_set_wedged(to_gt(i915));
+				intel_gt_set_wedged(engine->gt);
 				i915_request_put(rq);
 				break;
 			}