scsi: NCR5380: Reduce NCR5380_maybe_release_dma_irq() call sites

Refactor to avoid needless calls to NCR5380_maybe_release_dma_irq().
This makes the machine code smaller and the source more readable.

Link: https://lore.kernel.org/r/c1317ae8fdcb498460de5d7ea0bd62a42f5eeca8.1605847196.git.fthain@telegraphics.com.auTested-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/NCR5380.c

@@ -725,7 +725,6 @@ static void NCR5380_main(struct work_struct *work)
 
 			if (!NCR5380_select(instance, cmd)) {
 				dsprintk(NDEBUG_MAIN, instance, "main: select complete\n");
-				maybe_release_dma_irq(instance);
 			} else {
 				dsprintk(NDEBUG_MAIN | NDEBUG_QUEUES, instance,
 				         "main: select failed, returning %p to queue\n", cmd);
@@ -737,8 +736,10 @@ static void NCR5380_main(struct work_struct *work)
 			NCR5380_information_transfer(instance);
 			done = 0;
 		}
-		if (!hostdata->connected)
+		if (!hostdata->connected) {
 			NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
+			maybe_release_dma_irq(instance);
+		}
 		spin_unlock_irq(&hostdata->lock);
 		if (!done)
 			cond_resched();
@@ -1844,7 +1845,6 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance)
 					 */
 					NCR5380_write(TARGET_COMMAND_REG, 0);
 
-					maybe_release_dma_irq(instance);
 					return;
 				case MESSAGE_REJECT:
 					/* Accept message by clearing ACK */
@@ -1976,7 +1976,6 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance)
 					hostdata->busy[scmd_id(cmd)] &= ~(1 << cmd->device->lun);
 					cmd->result = DID_ERROR << 16;
 					complete_cmd(instance, cmd);
-					maybe_release_dma_irq(instance);
 					return;
 				}
 				msgout = NOP;
@@ -2312,7 +2311,6 @@ static int NCR5380_abort(struct scsi_cmnd *cmd)
 	}
 
 	queue_work(hostdata->work_q, &hostdata->main_task);
-	maybe_release_dma_irq(instance);
 	spin_unlock_irqrestore(&hostdata->lock, flags);
 
 	return result;
@@ -2368,7 +2366,6 @@ static void bus_reset_cleanup(struct Scsi_Host *instance)
 	hostdata->dma_len = 0;
 
 	queue_work(hostdata->work_q, &hostdata->main_task);
-	maybe_release_dma_irq(instance);
 }
 
 /**