IB/ipoib: Use new device FW version string

Using this allows for devices to specify the format of their
firmware version rather than forcing a format.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>