net: ethernet: ixp4xx: Add error handling in ixp4xx_eth_probe()

net: ethernet: ixp4xx: Add error handling in ixp4xx_eth_probe()

The function ixp4xx_eth_probe() does not perform sufficient error
checking after executing devm_ioremap_resource(), which can result
in crashes if a critical error path is encountered.

Fixes: 7a64d8707fdb ("ARM/net: ixp4xx: Pass ethernet physical base as resource")
Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>