clk: rockchip: rk3368: fix hdmi_cec gate-register

Fix a typo making the sclk_hdmi_cec access a wrong register to handle
its gate.

Fixes: 3536c97a ("clk: rockchip: add rk3368 clock controller")
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: zhangqing <zhangqing@rock-chips.com>
Cc: stable@vger.kernel.org