remoteproc: k3: update compatible for am654 syscon

remoteproc: k3: update compatible for am654 syscon

The existing compatible name for U-Boot's k3 system controller driver
i.e "ti,am625-system-controller" has been added to linux[1] device-tree.
This compatible in kernel is meant for configuring the Control Module
registers (CTRL_MMR0).

However in U-Boot, the matching driver was being used to load the system
firmware on the secure M-cores by the R5 SPL and therefore must be
updated to a different compatible to avoid conflicts.

Therefore, this patch renames all references of the compatible to
"ti,am654-tisci-rproc-r5". The "-r5" is appended so as to avoid any
future conflicts since r5 specific compatibles should only be useful for
U-Boot.

[1]: 5959618631fe ("dt-bindings: mfd: ti,j721e-system-controller: Add compatible string for AM654")
     https://lore.kernel.org/r/20250421214620.3770172-2-afd@ti.com

Signed-off-by: Anshul Dalal <anshuld@ti.com>