ARM: dts: ls1021a-tsn: update RGMII delays for sja1105 switch

In the new behavior, the sja1105 driver expects there to be explicit
RGMII delays present on the fixed-link ports, otherwise it will complain
that it falls back to legacy behavior, which is to apply RGMII delays
incorrectly derived from the phy-mode string.

In this case, the legacy behavior of the driver is to not apply delays
in any direction (mostly because the SJA1105T can't do that, so this
board uses PCB traces). To preserve that but also silence the driver,
use explicit delays of 0 ns. The delay information from the phy-mode is
ignored by new kernels (it's still RGMII as long as it's "rgmii*"
something), and the explicit {rx,tx}-internal-delay-ps properties are
ignored by old kernels, so the change works both ways.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>