arm64: dts: ti: k3-am62a7-sk: Split vcc_3v3 regulators

VCC_3V3_MAIN is the output of LM5141-Q1, and it serves as an input to
TPS22965DSGT which produces VCC_3V3_SYS. [1]

Link: https://www.ti.com/lit/zip/sprr459

 [1]
Signed-off-by: Jai Luthra <j-luthra@ti.com>
Reviewed-by: Devarsh Thakkar <devarsht@ti.com>
Link: https://lore.kernel.org/r/20231003-mcasp_am62a-v3-2-2b631ff319ca@ti.com


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