drm/i915/execlists: Avoid putting the error pointer

On allocation error, do not jump to the unwind handler that tries to
free the error pointer.
Reported-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: a89d1f92 ("drm/i915: Split i915_gem_timeline into individual timelines")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180611153332.14824-1-chris@chris-wilson.co.uk
(cherry picked from commit 467d3578)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_lrc.c

@@ -2641,10 +2641,8 @@ static int execlists_context_deferred_alloc(struct i915_gem_context *ctx,
 	context_size += LRC_HEADER_PAGES * PAGE_SIZE;
 
 	ctx_obj = i915_gem_object_create(ctx->i915, context_size);
-	if (IS_ERR(ctx_obj)) {
-		ret = PTR_ERR(ctx_obj);
-		goto error_deref_obj;
-	}
+	if (IS_ERR(ctx_obj))
+		return PTR_ERR(ctx_obj);
 
 	vma = i915_vma_instance(ctx_obj, &ctx->i915->ggtt.base, NULL);
 	if (IS_ERR(vma)) {