lasi_82594: use eth_hw_addr_set()

dev_addr is set from IO reads, passed to an arch-specific helper.
Note that the helper never reads it so uninitialized temp is fine.

Fixes build on parisc.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>