rework w83792d to use sensor-attr arrays

hi Yuan, everyone,

attached patch reworks w83792d to use sensor-attr arrays. this results in ~ 13K shrink in object code.

I dont have one of these chips, so this is compile-tested only,
but Winbond does ;-) and they're evidently supporting the driver (yay),
so Im hopeful that they will try this, and clean up the mistakes Ive inevitably made.