drm/drm_vma_manager.c: Remove useless goto statement

Commit db2395eccf08i ("drm: Convert drm_vma_manager to embedded
interval-tree in drm_mm") removed a line in drm_vma_offset_add() function that
makes checking the result of calling drm_mm_insert_node() and the goto
call redundant. Rework the function (as suggested by Chris Wilson) to
eliminate the need for the goto and associated label.

v2: rewrite function to remove all goto statements.

Fixes: db2395eccf08i ("drm: Convert drm_vma_manager to embedded interval-tree in drm_mm")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171101144458.5353-1-Liviu.Dudau@arm.com

drivers/gpu/drm/drm_vma_manager.c

@@ -203,21 +203,16 @@ EXPORT_SYMBOL(drm_vma_offset_lookup_locked);
 int drm_vma_offset_add(struct drm_vma_offset_manager *mgr,
 		       struct drm_vma_offset_node *node, unsigned long pages)
 {
-	int ret;
+	int ret = 0;
 
 	write_lock(&mgr->vm_lock);
 
-	if (drm_mm_node_allocated(&node->vm_node)) {
-		ret = 0;
-		goto out_unlock;
-	}
+	if (!drm_mm_node_allocated(&node->vm_node))
+		ret = drm_mm_insert_node(&mgr->vm_addr_space_mm,
+					 &node->vm_node, pages);
 
-	ret = drm_mm_insert_node(&mgr->vm_addr_space_mm, &node->vm_node, pages);
-	if (ret)
-		goto out_unlock;
-
-out_unlock:
 	write_unlock(&mgr->vm_lock);
+
 	return ret;
 }
 EXPORT_SYMBOL(drm_vma_offset_add);