PM / hibernate: Use CONFIG_HAVE_SET_MEMORY for include condition

Kbuild reported a build failure when CONFIG_STRICT_KERNEL_RWX was
enabled on powerpc. We don't yet have ARCH_HAS_SET_MEMORY and ppc32
saw a build failure.

I've only done a basic compile test with a config that has
hibernation enabled.

Fixes: 50327ddf (kernel/power/snapshot.c: use set_memory.h header)
Reported-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>