PM: suspend: add a arch_resume_nosmt() prototype

The arch_resume_nosmt() has a __weak definition, plus an x86
specific override, but no prototype that ensures the two have
the same arguments. This causes a W=1 warning:

arch/x86/power/hibernate.c:189:5: error: no previous prototype for 'arch_resume_nosmt' [-Werror=missing-prototypes]

Add the prototype in linux/suspend.h, which is included in
both places.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>