dt-bindings: net: renesas,etheravb: RZ/G2H needs tx-internal-delay-ps

The merge resolution of the interaction of commits 307eea32
("dt-bindings: net: renesas,ravb: Add support for r8a774e1 SoC") and
d7adf633 ("dt-bindings: net: renesas,etheravb: Convert to
json-schema") missed that "tx-internal-delay-ps" should be a required
property on RZ/G2H.

Fixes: 8b0308fe ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net"

)
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20210105151516.1540653-1-geert+renesas@glider.be


Signed-off-by: Jakub Kicinski <kuba@kernel.org>