Add usage details for reset command.
Signed-off-by: Igor Opaniuk <igor.opaniuk@foundries.io>
--- /dev/null
+.. SPDX-License-Identifier: GPL-2.0+
+
+reset command
+=============
+
+Synopsis
+--------
+
+::
+
+ reset [-w]
+
+Description
+-----------
+
+Perform reset of the CPU. By default does COLD reset, which resets CPU,
+DDR and peripherals, on some boards also resets external PMIC.
+
+-w
+ Do warm WARM, reset CPU but keep peripheral/DDR/PMIC active.
+
+
+Return value
+------------
+
+The return value $? is always set to 0 (true).