14.0 hardware: Update i386 and arm64 Tier information

Move arm64 earlier, so the two Tier 1 architectures are first. Add
other arm64 architectures (Ampere Computing and AWS). Tone down the
level of i386 support.

Reviewed by: carlavilla, philip
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D42593