net: fec: Convert to use devm_ioremap_resource

Commit 75096579 ("lib: devres: Introduce devm_ioremap_resource()")
introduced devm_ioremap_resource() and deprecated the use of
devm_request_and_ioremap().

Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
CC: netdev@vger.kernel.org
CC: "David S. Miller" <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>