dt-bindings: display: meson-dw-hdmi: add missing sound-name-prefix property

stable inclusion
from stable-v5.10.94
commit 66467cc87a353e4883af35b2d64ce0f6ac6e4bbb
bugzilla: https://gitee.com/openeuler/kernel/issues/I531X9

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=66467cc87a353e4883af35b2d64ce0f6ac6e4bbb



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commit 22bf4047 upstream.

This is used in meson-gx and meson-g12. Add the property to the binding.
This fixes the dtschema warning:
hdmi-tx@c883a000: 'sound-name-prefix' does not match any of the
regexes: 'pinctrl-[0-9]+'

Signed-off-by: Alexander Stein <alexander.stein@mailbox.org>
Fixes: 376bf52d ("dt-bindings: display: amlogic, meson-dw-hdmi: convert to yaml")
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211223122434.39378-2-alexander.stein@mailbox.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>