LU-9347 ioctl: Add BLKSSZGET ioctl support

LU-9347 ioctl: Add BLKSSZGET ioctl support

Add BLKSSZGET ioctl and return PAGE_SIZE for the minimun
alignment from ll_file_ioctl() for this call.

Lustre-change: https://review.whamcloud.com/28578
Lustre-commit: dcc32cd7d0d89a49f0c73ecf99130a2678442e55

Signed-off-by: Emoly Liu <emoly.liu@intel.com>
Change-Id: Id8a77e77cd7e1807aa90474ca6d3d1fea4d7c269
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Signed-off-by: Minh Diep <minh.diep@intel.com>
Reviewed-on: https://review.whamcloud.com/28861
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>