arm64: dts: rockchip: assign rate to clk_rtc_32k on rk356x

clk_rtc_32k and its child clock clk_hdmi_cec detauls to a rate of 24 MHz
and not to 32 kHz on RK356x.

Fix this by assigning clk_rtc_32k a rate of 32768, also assign the parent
to clk_rtc32k_frac.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Link: https://lore.kernel.org/r/20230110225547.1563119-2-jonas@kwiboo.se


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