RDMA: Allow for NULL .modify_device() and .modify_port() methods

These methods don't make sense for iWARP devices, so rather than
forcing them to implement stubs, just return -ENOSYS in the core if
the hardware driver doesn't set .modify_device and/or .modify_port.

Signed-off-by: Roland Dreier <roland@purestorage.com>
5 files changed