clk: clk-cdce925: Add regulator support

The cdce925 power supplies could be controllable on some platforms.
Enable them before communicating with the cdce925.

Signed-off-by: Phil Reid <preid@electromag.com.au>
Link: https://lkml.kernel.org/r/1561691950-42154-3-git-send-email-preid@electromag.com.au


Signed-off-by: Stephen Boyd <sboyd@kernel.org>