Create bsg device per controller for controller management purposes.

bsg device nodes will be named /dev/bsg/mpi3mrctl0, /dev/bsg/mpi3mrctl1,
etc.

Link: https://lore.kernel.org/r/20220429211641.642010-2-sumit.saxena@broadcom.comReported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>