arm64: dts: ti: k3-am62a7-sk: Enable ethernet port

AM62A7 SK has a DP83867 PHY on the board connected to first port of
CPSW, enable the same.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20230103042110.1092122-4-vigneshr@ti.com