mmc: atmel-mci: Simplify if(chan) and if(!chan)

Use if(!host->dma.chan) instead of if(chan) and if(!chan) to make
code better.
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Link: https://lore.kernel.org/r/20220427120310.838843-1-wanjiabing@vivo.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/atmel-mci.c

@@ -1122,13 +1122,12 @@ atmci_prepare_data_dma(struct atmel_mci *host, struct mmc_data *data)
 	}
 
 	/* If we don't have a channel, we can't do DMA */
-	chan = host->dma.chan;
-	if (chan)
-		host->data_chan = chan;
-
-	if (!chan)
+	if (!host->dma.chan)
 		return -ENODEV;
 
+	chan = host->dma.chan;
+	host->data_chan = chan;
+
 	if (data->flags & MMC_DATA_READ) {
 		host->dma_conf.direction = slave_dirn = DMA_DEV_TO_MEM;
 		maxburst = atmci_convert_chksize(host,