libpmc: count all AMD L3 cores, threads and slices by default

[ojanerif_amd.com]

Summary

Most AMD L3 event definitions do not set the thread, core or slice
selection, so they count zero. Select all of them when no thread mask
is given.

Sponsored by: AMD
Signed-off-by: Osvaldo Janeri Filho <[e-mail]>

[ali_mashtizadeh.com]

Oh man this came to byte us again, I’m looking at the json I need to think though a couple examples make sure its not breaking anything.

Also by the way I have that GitHub diff I need to refresh that fixes the userspace passing flags to overwrite these fields.

[ojanerif_amd.com]

Related: Hygon is family 18h and uses the 17h L3 layout, but libpmc and hwpmc both split at 0x17. I can fix that separately, or is it in your GitHub diff?