[PING][PATCH] Update documentation after dropping PER_THREAD conditional.

[Joseph S. Myers]

I now see build errors:

probes.texi:127: No matching `@end deftp'.
probes.texi:112: No matching `@end deftp'.

(this is from "make install", which builds the manual - generally "make 
info html pdf" is appropriate for testing doc patches).

-- 
Joseph S. Myers
joseph@codesourcery.com