USB: ehci-octeon: Use devm_ioremap_resource()

Use devm_ioremap_resource() to make cleanup paths simpler.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: David Daney <david.daney@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>