scsi: ibmvscsi_tgt: Fix dma_unmap_sg() nents value

The dma_unmap_sg() functions should be called with the same nents as the
dma_map_sg(), not the value the map function returned.

Fixes: 88a678b ("ibmvscsis: Initial commit of IBM VSCSI Tgt Driver")
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
Link: https://lore.kernel.org/r/20250630111803.94389-2-fourier.thomas@gmail.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: Thomas-fourier

drivers/scsi/ibmvscsi_tgt/libsrp.c

@@ -184,7 +184,8 @@ static int srp_direct_data(struct ibmvscsis_cmd *cmd, struct srp_direct_buf *md,
 	err = rdma_io(cmd, sg, nsg, md, 1, dir, len);
 
 	if (dma_map)
-		dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
+		dma_unmap_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
+			     DMA_BIDIRECTIONAL);
 
 	return err;
 }
@@ -256,7 +257,8 @@ static int srp_indirect_data(struct ibmvscsis_cmd *cmd, struct srp_cmd *srp_cmd,
 	err = rdma_io(cmd, sg, nsg, md, nmd, dir, len);
 
 	if (dma_map)
-		dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
+		dma_unmap_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
+			     DMA_BIDIRECTIONAL);
 
 free_mem:
 	if (token && dma_map) {