dt-bindings: display/msm: hdmi: mark hdmi-mux-supply as deprecated

dt-bindings: display/msm: hdmi: mark hdmi-mux-supply as deprecated

hdmi-mux-supply is not used by the SoC's HDMI block, it is thought to
power up the external logic. Thus it should not be a part of HDMI
bindings, but it should be declared at some other device in the DT (like
HDMI mux, bridge, etc). Mark it as deprecated.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/488870/
Link: https://lore.kernel.org/r/20220609122350.3157529-4-dmitry.baryshkov@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>