drivers: sm: bind child sm devices in the device tree

drivers: sm: bind child sm devices in the device tree

One well-known sm child device that provides secure power control is the
Secure Power Controller. This device utilizes SMC calls to communicate
with power domains on the secure monitor side.

Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
Signed-off-by: Alexey Romanov <avromanov@salutedevices.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20231101140500.9025-3-avromanov@salutedevices.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>