arm64: dts: ti: Add reserved memory for watchdog

This patch adds a reserved memory for the TI AM65X platform watchdog
to reserve the specific info, triggering the watchdog reset in last
boot, to know if the board reboot is due to a watchdog reset.

Signed-off-by: Li Hua Qian <huaqian.li@siemens.com>
Link: https://lore.kernel.org/r/20240117060654.109424-1-huaqian.li@siemens.com


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