audit: make functions static

I was doing some namespace checks and found some simple stuff in
audit that could be cleaned up. Make some functions static, and
put const on make_reply payload arg.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --cc kernel/audit.c
Simple merge

diff --cc kernel/audit.h
Simple merge

diff --cc kernel/audit_watch.c
Simple merge