arm64: dts: sdm845: Add "no-hpd" to sn65dsi86 on cheza

arm64: dts: sdm845: Add "no-hpd" to sn65dsi86 on cheza

We don't have the HPD line hooked up to the bridge chip.  Add it as
suggested in the patch ("dt-bindings: drm/bridge: ti-sn65dsi86:
Document no-hpd").

NOTE: this patch isn't expected to have any effect but just keeps us
cleaner for the future.  Currently the driver in Linux just assumes
that nobody has HPD hooked up.  This change allows us to later
implement HPD support in the driver without messing up sdm845-cheza.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20200507143354.v5.6.I89df9b6094549b8149aa8b8347f7401c678055b0@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>