The pclk pointer is only used in rockchip_mbox_probe() and is not needed after probe completes. Make it a local variable and drop it from struct rockchip_mbox, which saves a little bit of runtime memory. Signed-off-by: Linmao Li <lilinmao@kylinos.cn> Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>