clk: rockchip: add clock-id for HCLK_HDMI on rk3066

RK3066 and RK3188 share most of the clock controller but the rk3066 does
have an internal hdmi encoder and associated clock. Therefore add a
clock-id so that this clock can be used.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>