arm64: dts: ti: k3-am62a7-sk: Add alias for CPSW3G MAC port 1

Add alias for CPSW3G MAC port 1 to enable kernel to fetch MAC Address
directly from U-Boot.

Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>