arm64: dts: renesas: ulcb: add HDMI sound support

This patch adds missing ULCB HDMI sound support.
To use sound card, HDMI video is mandatory.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>