LU-13437 llite: pack parent FID in getattr

LU-13437 llite: pack parent FID in getattr

Pack parent FID in getattr request if OBD_CONNECT2_GETATTR_PFID is
enabled, otherwise fill it with target FID for backward compatibility.

Lustre-change: https://review.whamcloud.com/39290
Lustre-commit: 5f2c44bf626b178503c1c4d2d85c40bae087ff4f

Fixes: f9a2da63 ("LU-13437 mdt: don't fetch LOOKUP lock for remot...")
Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Change-Id: I91bace23e67b548feb92fd885fb5e64e92c96408
Reviewed-on: https://review.whamcloud.com/39771
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>