The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.
Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix
Summary: I've tested this with cpufreq_dt, SPI and USB. They all seem to work fine.
Test Plan: * IPQ4018, boot
Subscribers: imp, andrew
Differential Revision: https://reviews.freebsd.org/D33665