ethernet: sun: Free the coherent when failing in probing

[ Upstream commit bb77bd31c281f70ec77c9c4f584950a779e05cf8 ]

When the driver fails to register net device, it should free the DMA
region first, and then do other cleanup.

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>