Bluetooth: Add MacBookAir4,1 support

This patch against current git adds the hardware ID for the Apple
MacBookAir4,1, released in July 2011. The device features a BCM2046
USB chip. The patch was inspired by the previous modifications adding
support for the MacBookAir3,x.

Signed-off-by: Pieter-Augustijn Van Malleghem <p-a@scarlet.be>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>