drivers: bus: simple-pm-bus: Fix compatibility with simple-bus for auxdata

After converting am335x to probe devices with simple-pm-bus I noticed
that we are not passing auxdata for of_platform_populate() like we do
with simple-bus.

While device tree using SoCs should no longer need platform data, there
are still quite a few drivers that still need it as can be seen with
git grep OF_DEV_AUXDATA. We want to have simple-pm-bus be usable as a
replacement for simple-bus also for cases where OF_DEV_AUXDATA is still
needed.

Let's fix the issue by passing auxdata as platform data to simple-pm-bus.
That way the SoCs needing this can pass the auxdata with OF_DEV_AUXDATA.
And let's pass the auxdata for omaps to fix the issue for am335x.

As an alternative solution, adding simple-pm-bus handling directly to
drivers/of/platform.c was considered, but we would still need simple-pm-bus
device driver. So passing auxdata as platform data seems like the simplest
solution.

Fixes: 5a230524

 ("ARM: dts: Use simple-pm-bus for genpd for am3 l4_wkup")
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Tony Lindgren <tony@atomide.com>