qcom: bam_dma: Delete useless kfree code

The parameter of kfree function is NULL, so kfree code is useless, delete it.
Therefore, goto expression is no longer needed, so simplify it.
Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20201216130649.13979-1-zhengyongjun3@huawei.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/qcom/bam_dma.c

@@ -630,7 +630,7 @@ static struct dma_async_tx_descriptor *bam_prep_slave_sg(struct dma_chan *chan,
 			     GFP_NOWAIT);
 
 	if (!async_desc)
-		goto err_out;
+		return NULL;
 
 	if (flags & DMA_PREP_FENCE)
 		async_desc->flags |= DESC_FLAG_NWD;
@@ -670,10 +670,6 @@ static struct dma_async_tx_descriptor *bam_prep_slave_sg(struct dma_chan *chan,
 	}
 
 	return vchan_tx_prep(&bchan->vc, &async_desc->vd, flags);
-
-err_out:
-	kfree(async_desc);
-	return NULL;
 }
 
 /**