Fixed the SPI DMA transfer issue

@transfer_one: transfer a single spi_transfer.
- return 0 if the transfer is finished,
- return 1 if the transfer is still in progress. When
the driver is finished with this transfer it must
call spi_finalize_current_transfer() so the subsystem
can issue the next transfer. Note: transfer_one and
transfer_one_message are mutually exclusive; when both
are set, the generic subsystem does not call your
transfer_one callback.

Change-Id: Icd0b20c36dd4bfdc0928bd1dfd648950f972575f
Signed-off-by: yi-hsin_hung <yi-hsin_hung@asus.com>

Author: yihsin-hung

drivers/spi/spi-rockchip.c

@@ -499,7 +499,7 @@ static int rockchip_spi_prepare_dma(struct rockchip_spi *rs)
 		dma_async_issue_pending(rs->dma_tx.ch);
 	}
 
-	return 0;
+	return 1;
 }
 
 static void rockchip_spi_config(struct rockchip_spi *rs)