arm64: dts: ti: k3-am62p5-sk: Add regulator nodes for AM62P

arm64: dts: ti: k3-am62p5-sk: Add regulator nodes for AM62P

Add regulator node for AM62P-SK

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

VCC_3V3_SYS servers as vin-supply for peripherals like CSI [1].

Link: https://www.ti.com/lit/zip/sprr487
Reviewed-by: Devarsh Thakkar <devarsht@ti.com>
Signed-off-by: Rishikesh Donadkar <r-donadkar@ti.com>
Link: https://lore.kernel.org/r/20250502162539.322091-2-r-donadkar@ti.com
Signed-off-by: Nishanth Menon <nm@ti.com>