dt-bindings: watchdog: qcom-wdt: Document sram property

dt-bindings: watchdog: qcom-wdt: Document sram property

Document the "sram" property for the watchdog device on Qualcomm
IPQ platforms. Use this property to extract the restart reason from
IMEM, which is updated by XBL. Populate the watchdog's bootstatus sysFS
entry with this information, when the system reboots due to a watchdog
timeout.

Describe this property for the IPQ5424 watchdog device and extend support
to other targets subsequently.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260408-wdt_reset_reason-v10-1-caf66786329f@oss.qualcomm.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>