drm/i915/selftests: Remove erroneous intel_engine_pm_put

On an allocation error path for live_hwsp_alternate, we dropped the
engine wakeref before we had even acquired it.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200209131922.180287-4-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/selftest_timeline.c

@@ -606,7 +606,6 @@ static int live_hwsp_alternate(void *arg)
 
 			tl = checked_intel_timeline_create(gt);
 			if (IS_ERR(tl)) {
-				intel_engine_pm_put(engine);
 				err = PTR_ERR(tl);
 				goto out;
 			}