[SCSI] mvsas: remove mvs_slave_{alloc|configure}

libsas now handles:
1/ limiting ata scanning to lun0
2/ maximizing the queue_depth of sas devices (up to 256, mvsas only
   supports 64)
3/ changes to /sys/block/<sdX>/device/queue_depth for ata devices

Acked-by: Xiangliang Yu <yuxiangl@marvell.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>