net: netcp: ethss: enhancement to support NetCP 1.5 ethss

NetCP 1.5 available on newer K2 SoCs such as K2E and K2L introduced 3
variants of the ethss subsystem, 9 port, 5 port and 2 port. These have
one host port towards the CPU and N external slave ports.

To customize the driver for these new ethss sub systems, multiple
compatibility strings are introduced. Currently some of parameters that
are different on different variants such as number of ALE ports, stats
modules and number of ports are defined through constants. These are now
changed to variables in gbe_priv data that get set based on the
compatibility string. This is required as there are no hardware
identification registers available to distinguish among the variants
of NetCP 1.5 ethss. However there is identification register available
to differentiate between NetCP 1.4 vs NetCP 1.5 and the same is made use
of in the code to differentiate them.

For more reading on the details of this peripheral, please refer to the
User Guide available at http://www.ti.com/lit/pdf/spruhz3



Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: WingMan Kwok <w-kwok2@ti.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Mugunthan V N <mugunthanvnm@ti.com>
CC: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
CC: Grygorii Strashko <grygorii.strashko@ti.com>
CC: Christoph Jaeger <cj@linux.com>
CC: Lokesh Vutla <lokeshvutla@ti.com>
CC: Markus Pargmann <mpa@pengutronix.de>
CC: Kumar Gala <galak@codeaurora.org>
CC: Ian Campbell <ijc+devicetree@hellion.org.uk>
CC: Mark Rutland <mark.rutland@arm.com>
CC: Pawel Moll <pawel.moll@arm.com>
CC: Rob Herring <robh+dt@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>