drm/i915/lmem: fixup fake lmem teardown

We should not be unconditionally calling release_fake_lmem_bar.
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191106123135.12441-1-matthew.auld@intel.com

drivers/gpu/drm/i915/intel_region_lmem.c

@@ -51,7 +51,9 @@ static int init_fake_lmem_bar(struct intel_memory_region *mem)
 
 static void release_fake_lmem_bar(struct intel_memory_region *mem)
 {
-	if (drm_mm_node_allocated(&mem->fake_mappable))
+	if (!drm_mm_node_allocated(&mem->fake_mappable))
+		return;
+
 	drm_mm_remove_node(&mem->fake_mappable);
 
 	dma_unmap_resource(&mem->i915->drm.pdev->dev,