doc/usage: cmd: sm: documentation efusedump cmd

Added docs about sm efusedump command, that reads bytes
from efuse memory bank and print them to the console.

Signed-off-by: Alexey Romanov <avromanov@sberdevices.ru>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Link: https://lore.kernel.org/r/20230110105650.54580-6-avromanov@sberdevices.ru
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
diff --git a/doc/usage/cmd/sm.rst b/doc/usage/cmd/sm.rst
index c41227f..f6524a1 100644
--- a/doc/usage/cmd/sm.rst
+++ b/doc/usage/cmd/sm.rst
@@ -38,6 +38,10 @@
   Write into efuse memory bank, starting from <offset>, the <size> bytes
   of data, located at address <address>.
 
+sm efusedump
+  Read <size> bytes starting from <offset> from efuse memory bank and print
+  them to the console.
+
 Configuration
 -------------