drm/prime: Remove PRIME handles only if supported

Drivers that don't support PRIME will not have initialized the PRIME
specific private component of struct drm_file. If called for such
drivers, the drm_gem_remove_prime_handles() function will crash. Fix
it by checking for PRIME support prior to removing the PRIME handles.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index b2d59b2..49293bdc 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -297,7 +297,8 @@
 	idr_remove(&filp->object_idr, handle);
 	spin_unlock(&filp->table_lock);
 
-	drm_gem_remove_prime_handles(obj, filp);
+	if (drm_core_check_feature(dev, DRIVER_PRIME))
+		drm_gem_remove_prime_handles(obj, filp);
 	drm_vma_node_revoke(&obj->vma_node, filp->filp);
 
 	if (dev->driver->gem_close_object)
@@ -706,7 +707,8 @@
 	struct drm_gem_object *obj = ptr;
 	struct drm_device *dev = obj->dev;
 
-	drm_gem_remove_prime_handles(obj, file_priv);
+	if (drm_core_check_feature(dev, DRIVER_PRIME))
+		drm_gem_remove_prime_handles(obj, file_priv);
 	drm_vma_node_revoke(&obj->vma_node, file_priv->filp);
 
 	if (dev->driver->gem_close_object)