arm64: dts: ti: k3-am642-evm: Set delay values for DP83869 Tx/Rx

The Tx and Rx delay values affect CPSW Port 2 / ICSSG Port 1/2.
This patch sets the Tx and Rx delay values as below for DP83869
in order to gain stability.

Tx delay - 250ps
Rx delay - 2ns

Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>