vmxnet3: Move some definitions to header file

vmxnet3: Move some definitions to header file

pvrdma setup requires vmxnet3 device on PCI function 0 and PVRDMA device
on PCI function 1.
pvrdma device needs to access vmxnet3 device object for several reasons:
1. Make sure PCI function 0 is vmxnet3.
2. To monitor vmxnet3 device state.
3. To configure node_guid accoring to vmxnet3 device's MAC address.

To be able to access vmxnet3 device the definition of VMXNET3State is
moved to a new header file.

Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
Reviewed-by: Dmitry Fleytman <dmitry.fleytman@gmail.com>
Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>