kill LOOKUP_NO_EVAL, don't bother including namei.h from audit.h

The former has no users left; the latter was only to get LOOKUP_...
values to remapper in audit_inode() and that's an ex-parrot now.

All places that use symbols from namei.h include it either directly
or (in a few cases) via a local header, like fs/autofs/autofs_i.h

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>