net: axienet: Preparatory changes for dmaengine support

The axiethernet driver has inbuilt dma programming. In order to add
dmaengine support and make it's integration seamless the current axidma
inbuilt programming code is put under use_dmaengine check.

It also performs minor code reordering to minimize conditional
use_dmaengine checks and there is no functional change. It uses
"dmas" property to identify whether it should use a dmaengine
framework or inbuilt axidma programming.
Signed-off-by: Sarath Babu Naidu Gaddam <sarath.babu.naidu.gaddam@amd.com>
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Link: https://lore.kernel.org/r/1700074613-1977070-3-git-send-email-radhey.shyam.pandey@amd.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/xilinx/xilinx_axienet.h

@@ -435,6 +435,7 @@ struct axidma_bd {
  * @coalesce_usec_rx:	IRQ coalesce delay for RX
  * @coalesce_count_tx:	Store the irq coalesce on TX side.
  * @coalesce_usec_tx:	IRQ coalesce delay for TX
+ * @use_dmaengine: flag to check dmaengine framework usage.
  */
 struct axienet_local {
 	struct net_device *ndev;
@@ -499,6 +500,7 @@ struct axienet_local {
 	u32 coalesce_usec_rx;
 	u32 coalesce_count_tx;
 	u32 coalesce_usec_tx;
+	u8  use_dmaengine;
 };
 
 /**