hwmon/pc87360 separate alarm files: define LDNI_MAX const

Driver handles 3 logical devices in fixed length array.  Give this a
define-d constant.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: "Mark M. Hoffman" <mhoffman@lightlink.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>