bus: simple-pm-bus: fix forced runtime PM use

bus: simple-pm-bus: fix forced runtime PM use

The simple-pm-bus driver only enables runtime PM for some buses
('simple-pm-bus') yet has started calling pm_runtime_force_suspend() and
pm_runtime_force_resume() during system suspend unconditionally.

This currently works, but that is not obvious and depends on
implementation details which may change at some point.

Add dedicated system sleep ops and only call pm_runtime_force_suspend()
and pm_runtime_force_resume() for buses that use runtime PM to avoid any
future surprises.

Fixes: c45839309c3d ("drivers: bus: simple-pm-bus: Use clocks")
Cc: Liu Ying <victor.liu@nxp.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Liu Ying <victor.liu@nxp.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20250214102130.3000-1-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>