Remove the bus clock from the mdss device node, in order to facilitate
bus band width scaling on sm8250 target.

The parent device MDSS will not vote for bus bw, instead the vote will
be triggered by mdp device node. Since a minimum vote is required to
turn on bus clock, and since mdp device node already has the bus clock,
remove the clock from the mdss device.
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20210803101657.1072358-3-dmitry.baryshkov@linaro.orgSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>