In dual_emac mode the driver can handle 2 network devices. Each of them can use
its own private data and common data/resources. This patchset splits common driver
data/resources and private per net device data.
It leads to:
- reduce memory usage
- increase code readability
- allows add a bunch of simplification
- create prerequisites to add multi-channel support,
when channels are shared between net devices
Doesn't have bad impact on performance.
v1: https://lkml.org/lkml/2016/8/4/616