perf namespaces: Move the conditional setns() prototype to namespaces.h

Out of util.h, to reduce its scope, and since we have a namespaces.h
header, much better to have it there, where it is related to.

Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
3 files changed