arm64: dts: ti: k3-am654-base-board: Add VTT GPIO regulator for DDR

Hold the DDR vtt regulator active for functionality.

Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Kamlesh Gurudasani <kamlesh@ti.com>
Link: https://lore.kernel.org/r/20230419225913.663448-4-nm@ti.com


Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>