arm64: dts: ti: k3-j7200-main: Add SERDES and WIZ device tree node

Add dt node for the single instance of WIZ (SERDES wrapper) and
SERDES module shared by PCIe, CPSW (SGMII/QSGMII) and USB.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20210105151421.23237-4-kishon@ti.com