ravb: Add internal delay hw feature to struct ravb_hw_info

R-Car Gen3 supports TX and RX clock internal delay modes, whereas R-Car
Gen2 and RZ/G2L do not support it.
Add an internal_delay hw feature bit to struct ravb_hw_info to enable this
only for R-Car Gen3.

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>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>