arm64: dts: ti: k3-am62a7-sk: Reserve main_rti4 for C7x DSP

The main rti4 watchdog timer is used by the C7x DSP, so reserve the
timer in the linux device tree.

Signed-off-by: Hari Nagalla <hnagalla@ti.com>
Signed-off-by: Judith Mendez <jm@ti.com>
Reviewed-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20250502220325.3230653-11-jm@ti.com


Signed-off-by: Nishanth Menon <nm@ti.com>