dt-bindings: clock: Require #reset-cells in sdm845-videocc

dt-bindings: clock: Require #reset-cells in sdm845-videocc

The #reset-cells was listed as optional in the bindings for
qcom,sdm845-videocc.  There's no reason for it to be optional.  As per
Stephen [1]:

> We should update the binding to make it a required property. It
> doesn't make any sense why that property would be optional given
> that the hardware either has support for resets or it doesn't.

sdm845 support is still in its infancy so we shouldn't be affecting
any real device trees by modifying the bindings here.

[1] https://lkml.kernel.org/r/154330186815.88331.12720647562079303842@swboyd.mtv.corp.google.com

Fixes: 84b66b211603 ("dt-bindings: clock: Introduce QCOM Video clock bindings")
Suggested-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>