Revision 202284

- Update required headers for namei() to add <sys/fcntl.h> and remove
  <sys/proc.h>.
- Add RETURN VALUES and ERROR sections for namei()'s error return values.
- Add a missing link to NDHASGIANT.9.

PR:		docs/142815, docs/142816
Submitted by:	Lachlan Kang (1, 2)
MFC after:	3 days