ravb: Add struct ravb_hw_info to driver data

The DMAC and EMAC blocks of Gigabit Ethernet IP found on RZ/G2L SoC are
similar to the R-Car Ethernet AVB IP. With a few changes in the driver we
can support both IPs.

This patch adds the struct ravb_hw_info to hold hw features, driver data
and function pointers to support both the IPs. It also replaces the driver
data chip type with struct ravb_hw_info by moving chip type to it.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>