simple_strto*() are obsolete; use kstrto*() instead. Add proper error
checking.
Signed-off-by: NChristoph Jaeger <christophjaeger@linux.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>