Enhance Armada 38x SoC identification string
Add hw_clockrate and CPU frequency, basing on sample-at-reset
configuration.
Submitted by: Arnaud Ysmal <arnaud.ysmal@stormshield.eu>
Marcin Wojtas <mw@semihalf.com>
Obtained from: Stormshield, Semihalf
Sponsored by: Stormshield
Reviewed by: andrew
Differential revision: https://reviews.freebsd.org/D10899