Backport of a4eef43a12 ("ath79: ag71xx: replace alloc_etherdev with devm_alloc_etherdev")
combined with the initial changes from John Crispin.
Simplifies the code a lot by using the Managed dev API.
Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
19ed799bdc