arm: dts: k3-j7200: Add R5 specific dts support

Add the basic a72 basic dts for j7200. Following nodes were supported:
- UART
- MMC SD
- I2C
- TISCI communication
- LPDDR with 1600MTs configuration.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>