AR2315 Ethernet driver pass NULL instead of a real device pointer to DMA
(un-)map calls. With kernel version 5.4 such behaviour causes a kernel
panic. Fix this issue by preserving device pointer during the probe
procedure and pass it to each skb data DMA (un-)map call.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
ce3b135243