drm/vmwgfx: Remove the repeated declaration

Function 'vmw_context_binding_list' is declared twice, remove the
repeated declaration.

Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
Cc: Roland Scheidegger <sroland@vmware.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Zack Rusin <zackr@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1621930170-54923-1-git-send-email-zhangshaokun@hisilicon.com

drivers/gpu/drm/vmwgfx/vmwgfx_drv.h

@@ -1295,7 +1295,6 @@ extern struct vmw_cmdbuf_res_manager *
 vmw_context_res_man(struct vmw_resource *ctx);
 extern struct vmw_resource *vmw_context_cotable(struct vmw_resource *ctx,
 						SVGACOTableType cotable_type);
-extern struct list_head *vmw_context_binding_list(struct vmw_resource *ctx);
 struct vmw_ctx_binding_state;
 extern struct vmw_ctx_binding_state *
 vmw_context_binding_state(struct vmw_resource *ctx);