target: Change TCM_NON_EXISTENT_LUN response to ASC=LOGICAL UNIT NOT SUPPORTED

This patch changes transport_send_check_condition_and_sense() for
TCM_NON_EXISTENT_LUN emulation to use 0x25 (LOGICAL UNIT NOT SUPPORTED)
instead of the original 0x20 (INVALID COMMAND OPERATION CODE).  This is
helpful to distinguish between TCM_UNSUPPORTED_SCSI_OPCODE ASC=0x20
exceptions.
Signed-off-by: NNicholas A. Bellinger <nab@risingtidesystems.com>

drivers/target/target_core_transport.c

@@ -4726,6 +4726,13 @@ int transport_send_check_condition_and_sense(
 	 */
 	switch (reason) {
 	case TCM_NON_EXISTENT_LUN:
+		/* CURRENT ERROR */
+		buffer[offset] = 0x70;
+		/* ILLEGAL REQUEST */
+		buffer[offset+SPC_SENSE_KEY_OFFSET] = ILLEGAL_REQUEST;
+		/* LOGICAL UNIT NOT SUPPORTED */
+		buffer[offset+SPC_ASC_KEY_OFFSET] = 0x25;
+		break;
 	case TCM_UNSUPPORTED_SCSI_OPCODE:
 	case TCM_SECTOR_COUNT_TOO_MANY:
 		/* CURRENT ERROR */