[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>
diff --git a/drivers/misc/enclosure.c b/drivers/misc/enclosure.c
index e9eae4a..1eac626 100644
--- a/drivers/misc/enclosure.c
+++ b/drivers/misc/enclosure.c
@@ -391,6 +391,7 @@
 	[ENCLOSURE_STATUS_NOT_INSTALLED] = "not installed",
 	[ENCLOSURE_STATUS_UNKNOWN] = "unknown",
 	[ENCLOSURE_STATUS_UNAVAILABLE] = "unavailable",
+	[ENCLOSURE_STATUS_MAX] = NULL,
 };
 
 static const char *const enclosure_type [] = {