Marvell Sky2 Ethernet adapter: fix warning messages.

sky2.c driver uses netdev_warn() before the net device is initialized.
Fix it by using dev_warn() instead.

Signed-off-by: Krzysztof Halasa <khalasa@piap.pl>

Link: https://lore.kernel.org/r/m3a6s1r1ul.fsf@t19.piap.pl


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