net: usb: ax88179_178a: allow passing MAC via DTB

From: Peter Fink <redacted>

This is a resend of the following patch as net-next was closed before:

I adopted the feature to pass the MAC address through device tree
from asix_devices.c (introduced in 03fc5d4) to ax88179-based devices.
Please have a look if this patch can be accepted.

I introduced a new function to avoid code duplication, but I'm not perfectly
satisfied with the function name. Suggestions welcome.

I'm not totally sure if the use of net->dev_addr and net->perm_addr
was correct in the first place or if my understanding is lacking some bits.
But I kept the existing behavior as it is working as expected.

Patch tested with 4.19, but applies cleanly on net-next.

Best regards,
Peter

--

 drivers/net/usb/ax88179_178a.c | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

-- 
2.7.4