net: sparx5: add port module support

This add configuration of the Sparx5 port module instances.

Sparx5 has in total 65 logical ports (denoted D0 to D64) and 33
physical SerDes connections (S0 to S32).  The 65th port (D64) is fixed
allocated to SerDes0 (S0). The remaining 64 ports can in various
multiplexing scenarios be connected to the remaining 32 SerDes using
QSGMII, or USGMII or USXGMII extenders. 32 of the ports can have a 1:1
mapping to the 32 SerDes.

Some additional ports (D65 to D69) are internal to the device and do not
connect to port modules or SerDes macros. For example, internal ports are
used for frame injection and extraction to the CPU queues.

The 65 logical ports are split up into the following blocks.

- 13 x 5G ports (D0-D11, D64)
- 32 x 2G5 ports (D16-D47)
- 12 x 10G ports (D12-D15, D48-D55)
- 8 x 25G ports (D56-D63)

Each logical port supports different line speeds, and depending on the
speeds supported, different port modules (MAC+PCS) are needed. A port
supporting 5 Gbps, 10 Gbps, or 25 Gbps as maximum line speed, will have a
DEV5G, DEV10G, or DEV25G module to support the 5 Gbps, 10 Gbps (incl 5
Gbps), or 25 Gbps (including 10 Gbps and 5 Gbps) speeds. As well as, it
will have a shadow DEV2G5 port module to support the lower speeds
(10/100/1000/2500Mbps). When a port needs to operate at lower speed and the
shadow DEV2G5 needs to be connected to its corresponding SerDes

Not all interface modes are supported in this series, but will be added at
a later stage.

Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
Signed-off-by: Bjarni Jonasson <bjarni.jonasson@microchip.com>
Signed-off-by: Lars Povlsen <lars.povlsen@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>