Remove sparc64 stuff from usr.sbin

[imp]

Summary

Note: this is multiple commits in one review since I don't modify a file I later delete

Remove sparc64 example.

Remove sparc64 ifdef

Now we default to setting the hardware clock to UTC
everywhere. sparc64 was the old odd-man out before.

Fix comment. It mentioned sparc64 specifically, but alignment issues are present elsewhere.

Fix a comment for the SUN geom class.

For valid arch values (really $MACHINE), remove references to alpha and sparc64. Add references to arm64 and riscv

Remove sparc64 specific eeprom command

This command was only ever for sparc64, so remove it. Remove
usr.sbin/Makeiile.sparc64 as well since it only references ofwdump
(cross platform) and eeprom.

Refresh architecture list with latest:

Remove: sparc, sparc64 (twice), ia64, alpha
Add: riscv64

Remove now-useless sparc64 ifdef

Remove ifdefs for ia64 and sparc64.

[imp]

usr.sbin/bsnmpd/modules/snmp_hostres/hostres_partition_tbl.c

485–494 ↗

(On Diff #68020)

Note: I plan on removing SUN label geom support in a separate pass through the tree.
There's other issues at play, and I think that this is subsumed already by gpart and I want to sort out that confusion first.

[bcr]

OK for the manpage changes. The binmiscctl.8 also needs a .Dd bump (content change).

[cy]