arm64: dts: freescale: imx93-phycore-som: Delay the phy reset by a gpio

arm64: dts: freescale: imx93-phycore-som: Delay the phy reset by a gpio

According to the datasheet the phy needs to be held in reset until the
reference clock got stable. Even though no issue was observed, fix this
as the software should always comply with the specification.

Use gpio4 23, which is connected to the phy reset pin. On the same pin
RX_ER was used before, but this signal is optional and can be dropped.

Note: This comes into effect with the phyCOREs SOM hardware revision 4.
In revisions before, this gpio is not connected, and the phy reset is
managed with the global hardware reset circuit.

Signed-off-by: Christoph Stoidner <c.stoidner@phytec.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>