scsi: be2iscsi: Replace _bh version for mcc_lock spinlock

This got unnecessarily introduced with other changes in previous
commits. mcc_lock is taken only in process contexts.

Signed-off-by: Jitendra Bhivare <jitendra.bhivare@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>