arm64: dts: amlogic: setup hdmi system clock

arm64: dts: amlogic: setup hdmi system clock

HDMI Tx needs the system clock set on the xtal rate.
This clock is managed by the main clock controller of the related SoCs.

Currently 2 part of the display drivers race to setup the HDMI system
clock by directly poking the controller register. The clock API should
be used to setup the rate instead.

Use assigned-clock to setup the HDMI system clock.

Fixes: 6939db7e0dbf ("ARM64: dts: meson-gx: Add support for HDMI output")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20240626152733.1350376-3-jbrunet@baylibre.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>