PM / hibernate: Fix memory corruption in resumedelay_setup()

In the original code "resume_delay" is an int so on 64 bits, the call to
kstrtoul() will cause memory corruption.  We may as well fix a style
issue here as well and make "resume_delay" unsigned int, since that's
what we pass to ssleep().

Fixes: 317cf7e5

 (PM / hibernate: convert simple_strtoul to kstrtoul)
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>