drm/vmwgfx: Persistent tracking of context bindings

Only scrub context bindings when a bound resource is destroyed, or when
the MOB backing the context is unbound.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Zack Rusin <zackr@vmware.com>
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index fb56676..9008a56 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -612,6 +612,7 @@
 	mutex_init(&dev_priv->hw_mutex);
 	mutex_init(&dev_priv->cmdbuf_mutex);
 	mutex_init(&dev_priv->release_mutex);
+	mutex_init(&dev_priv->binding_mutex);
 	rwlock_init(&dev_priv->resource_lock);
 
 	for (i = vmw_res_context; i < vmw_res_max; ++i) {