Some EtherAVB variants support internal clock delay configuration, which
can add larger delays than the delays that are typically supported by
the PHY (using an "rgmii-*id" PHY mode, and/or "[rt]xc-skew-ps"
properties).

Historically, the EtherAVB driver configured these delays based on the
"rgmii-*id" PHY mode.  This was wrong, as these are meant solely for the
PHY, not for the MAC.  Hence properties were introduced for explicit
configuration of these delays.

Convert the R-Car Gen3 DTS files from the old to the new scheme:
  - Add default "rx-internal-delay-ps" and "tx-internal-delay-ps"
    properties to the SoC .dtsi files, to be overridden by board files
    where needed,
  - Convert board files from "rgmii-*id" PHY modes to "rgmii", adding
    the appropriate "rx-internal-delay-ps" and/or "tx-internal-delay-ps"
    overrides.

Notes:
  - R-Car E3 and D3 do not support TX internal delay handling,
  - On R-Car D3, TX internal delay handling must always be enabled,
    hence this fixes a bug on Draak,
  - On R-Car V3H, RX internal delay handling must always be enabled.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200819134344.27813-7-geert+renesas@glider.be