LU-14648 lod: protect lod_object layout info

LU-14648 lod: protect lod_object layout info

Need to protect lod_object's layout access with ldo_layout_mutex.

Lustre-commit: 25aa8527374f8120c113dc12adb1366a1ab98152
Lustre-change: https://review.whamcloud.com/43671

Signed-off-by: Bobi Jam <bobijam@whamcloud.com>
Change-Id: I2c4a2078bdce64d15485d3ff18f6670d42ca90ba
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: John L. Hammond <jhammond@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/44256
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>