clk: rockchip: Fix memory leak in rockchip_clk_register_pll()

If clk_register() fails, @pll->rate_table may have allocated memory by
kmemdup(), so it needs to be freed, otherwise will cause memory leak
issue, this patch fixes it.

Fixes: 90c59025

 ("clk: rockchip: add clock type for pll clocks and pll used on rk3066")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Link: https://lore.kernel.org/r/20221123091201.199819-1-xiujianfeng@huawei.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>