ARM / PXA: Use struct syscore_ops for "core" power management

Replace sysdev classes and struct sys_device objects used for "core"
power management by the PXA platform code with struct syscore_ops
objects that are simpler.

This reduces the code size and the kernel memory footprint.  It also
is necessary for removing sysdevs entirely from the kernel in the
future.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

arch/arm/mach-pxa/vpac270.c

@@ -16,7 +16,6 @@
 #include <linux/gpio_keys.h>
 #include <linux/input.h>
 #include <linux/gpio.h>
-#include <linux/sysdev.h>
 #include <linux/usb/gpio_vbus.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>