clk: scmi: Support atomic clock enable/disable API

clk: scmi: Support atomic clock enable/disable API

Support also atomic enable/disable clk_ops beside the bare non-atomic one
(prepare/unprepare) when the underlying SCMI transport is configured to
support atomic transactions for synchronous commands.

Compare the SCMI system-wide configured atomic threshold latency time and
the per-clock advertised enable latency (if any) to choose whether to
provide sleeping prepare/unprepare vs atomic enable/disable.

Link: https://lore.kernel.org/r/20220213195832.27932-9-cristian.marussi@arm.com
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: linux-clk@vger.kernel.org
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>