[SCSI] enclosure: fix oops while iterating enclosure_status array

[SCSI] enclosure: fix oops while iterating enclosure_status array

Based on patch originally by Jeff Mahoney <jeffm@suse.com>

 enclosure_status is expected to be a NULL terminated array of strings
 but isn't actually NULL terminated. When writing an invalid value to
 /sys/class/enclosure/.../.../status, it goes off the end of the array
 and Oopses.

Fix by making the assumption true and adding NULL at the end.

Reported-by: Artur Wojcik <artur.wojcik@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>