ACPI / Sleep: Free NVS copy if suspending of devices fails

If suspending of devices fails or system suspend is tested in the
"devices" mode, the memory allocated for storing a copy of the ACPI
NVS area will not be freed, because acpi_pm_finish() is not called
in that case.  Fix this by moving the suspend_nvs_free() call to
acpi_pm_end().

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>