asmc: Add support for 10 byte light sensor payloads; MacBookAir6,1

The later macbook models use a different packet payload for the light
sensors:

• There's only one, done in the camera
• It's a 4 byte sensor value, not a 2 byte value
• It's in a 10 byte payload.

So, this adds support for that and flips it on for the MacbookAir6,2.

It also adds support for MacBookAir6,1 as that now works fine here.

Tested - MacBookAir6,1 and 6,2

Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D38365