Remove extraneous request cancel in request allocation failure path
in intel_lr_context_deferred_alloc (Tvrtko Ursulin)
Regression from:
  commit 
e84fe80337dc85cca07d0417ea97edbec4789d8b
  Author: Nick Hoath <nicholas.hoath@intel.com>
  Date:   Fri Sep 11 12:53:46 2015 +0100
      drm/i915: Split alloc from init for lrc
Signed-off-by: Nick Hoath <nicholas.hoath@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
 
                if (ret) {
                        DRM_ERROR("ring create req: %d\n",
                                ret);
-                       i915_gem_request_cancel(req);
                        goto error_ringbuf;
                }