switch vfs_path_lookup() to struct path

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

diff --cc fs/namei.c
Simple merge

diff --cc fs/nfs/cache_lib.c
Simple merge

diff --cc fs/nfs/super.c
Simple merge

diff --cc include/linux/namei.h
Simple merge

diff --cc net/sunrpc/clnt.c
Simple merge