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.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>