arm64: dts: ti: Introduce base support for AM6254atl SiP

arm64: dts: ti: Introduce base support for AM6254atl SiP

This patch adds the top level dtsi for AM6254atl SiP which integrates
the existing AM625 SoC with 512MiB of DDR in a single package.

More information about the package can be found here:
https://www.ti.com/lit/ds/symlink/am625sip.pdf

Signed-off-by: Anshul Dalal <anshuld@ti.com>
Reviewed-by: Bryan Brattlof <bb@ti.com>
Link: https://patch.msgid.link/20250814134531.2743874-4-anshuld@ti.com
Signed-off-by: Nishanth Menon <nm@ti.com>
[ upstream commit: 7c1d13a14e61ab33eec330cb6cabbddb37eecaa9 ]

(cherry picked from commit fa5a6a6e784bde78c6ec74eccd92d51fb9fd49e8)