clk: qcom: gdsc: Use PM clocks to control gdsc clocks

clk: qcom: gdsc: Use PM clocks to control gdsc clocks

The devices within a gdsc power domain, quite often have additional
clocks to be turned on/off along with the power domain itself.
Once the drivers for these devices are converted to use runtime PM,
it would be possible to remove all clock handling from the drivers if
the gdsc driver can handle it.
Use PM clocks to add support for this. A list of clock ids specified
per gdsc would be the clocks turned on/off on every device start/stop
callbacks.

Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>