net: asix: Fix AX88772B when used with DriverModel

A previous patch (net: asix: fix operation without eeprom) added a
two-byte shift to the packet buffer when receiving a packet on the
AX88772B.

This shift was not included when the driver was updated to work with
DriverModel. Testing on a Marvell DB-88F6820-ACM showed that the adapter
was not functioning correctly (EHCI timeouts).

This patch brings the two-byte shift to the DriverModel implementation
of ops->recv (asix_eth_recv).

Testing on the same board, we were able to TFTP a file over and confirm
that the crc32 was correct.

Signed-off-by: Joshua Scott <joshua.scott@alliedtelesis.co.nz>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>