arm64: dts: ti: k3-j721e-sk: Define aliases at board level

Define the aliases at the board level instead of using generic aliases
at SoC level.

Signed-off-by: Nishanth Menon <nm@ti.com>
Link: https://lore.kernel.org/r/20230601183151.1000157-8-nm@ti.com


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