scsi: mpi3mr: Free enclosure objects during driver unload

Free the enclosure device objects during driver unload and before
rescanning the target devices during controller reset.

Link: https://lore.kernel.org/r/20220912135742.11764-7-sreekanth.reddy@broadcom.com


Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>