LU-5456 hsm: hold inode mutex around ll_setattr_raw()

LU-5456 hsm: hold inode mutex around ll_setattr_raw()

ll_setattr_raw() expects to be called with the inode mutex held so do
when calling it from ll_hsm_import().

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I91ef3d431fdf6db23bf4be6e957f2981d3e016cd
Reviewed-on: http://review.whamcloud.com/11349
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: Faccini Bruno <bruno.faccini@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>