dt-bindings: clock: Add sc7180 GCC clock binding

Add device tree bindings for global clock subsystem clock
controller for Qualcomm Technology Inc's SC7180 SoCs.

Signed-off-by: Taniya Das <tdas@codeaurora.org>
Link: https://lkml.kernel.org/r/20191014102308.27441-5-tdas@codeaurora.org


Reviewed-by: Rob Herring <robh@kernel.org>
[sboyd@kernel.org: Reword subject to make sc7180 specific, sort
compatible]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>