scsi: mpi3mr: Unlock on error path

There is some clean up necessary before returning.  Smatch complains:

    drivers/scsi/mpi3mr/mpi3mr_fw.c:4786 mpi3mr_soft_reset_handler()
    warn: inconsistent returns '&mrioc->reset_mutex'.
      Locked on  : 4730
      Unlocked on: 4786

Link: https://lore.kernel.org/r/YtVCEsxMU8buuMjP@kili
Fixes: f10af05732 ("scsi: mpi3mr: Resource Based Metering")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/mpi3mr/mpi3mr_fw.c

@@ -4727,7 +4727,8 @@ int mpi3mr_soft_reset_handler(struct mpi3mr_ioc *mrioc,
 		    "max io throttle group doesn't match old(%d), new(%d)\n",
 		    mrioc->num_io_throttle_group,
 		    mrioc->facts.max_io_throttle_group);
-		return -EPERM;
+		retval = -EPERM;
+		goto out;
 	}
 
 	mpi3mr_flush_delayed_cmd_lists(mrioc);