drivers: dma: siwx91x: Simplify descriptors list creation

The management of the single-linked list was made in various places:
  - RSI_GPDMA_BuildDescriptors()
  - after sys_mem_blocks_alloc()
  - at the end of the loop

Centralize it at the end of the loop.

Signed-off-by: Jérôme Pouiller <[email protected]>

Author: jerome-pouiller

drivers/dma/dma_silabs_siwx91x_gpdma.c

@@ -170,14 +170,10 @@ static int siwx91x_gpdma_desc_config(struct siwx19x_gpdma_data *data,
 			goto free_desc;
 		}
 
-		if (prev_desc == NULL) {
-			data->chan_info[channel].desc = cur_desc;
-		}
-
 		memset(cur_desc, 0, 32);
 
 		ret = RSI_GPDMA_BuildDescriptors(&data->hal_ctx, (RSI_GPDMA_DESC_T *)xfer_cfg,
-						 cur_desc, prev_desc);
+						 cur_desc, NULL);
 		if (ret) {
 			goto free_desc;
 		}
@@ -194,6 +190,12 @@ static int siwx91x_gpdma_desc_config(struct siwx19x_gpdma_data *data,
 			cur_desc->chnlCtrlConfig.srcFifoMode = 1;
 		}
 
+
+		if (prev_desc) {
+			prev_desc->pNextLink = (void *)cur_desc;
+		} else {
+			data->chan_info[channel].desc = cur_desc;
+		}
 		prev_desc = cur_desc;
 		block_addr = block_addr->next_block;
 	}