Update Annapurna Alpine HAL to a newer version.
HAL version: 2.7a

Import from vendor-sys, r305475

Import Annapurna Labs Alpine HAL to sys/contrib/

Import from vendor-sys/alpine-hal/2.7
SVN rev.: 285432
HAL version: 2.7

Obtained from: Semihalf
Sponsored by: Annapurna Labs