cpuidle: Adjust includes to remove of_device.h

Now that of_cpu_device_node_get() is defined in of.h, of_device.h is just
implicitly including other includes, and is no longer needed. Adjust the
include files with what was implicitly included by of_device.h (cpu.h,
cpuhotplug.h, of.h, and of_platform.h) and drop including of_device.h.

Acked-by: Anup Patel <anup@brainfault.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20230329-dt-cpu-header-cleanups-v1-16-581e2605fe47@kernel.org


Signed-off-by: Rob Herring <robh@kernel.org>