firmware: meson_sm: populate platform devices from sm device tree data

In some meson boards, secure monitor device has children, for example,
power secure controller. By default, secure monitor isn't the bus in terms
of device tree subsystem, so the of_platform initialization code doesn't
populate its device tree data. As a result, secure monitor's children
aren't probed at all.

Run the 'of_platform_populate()' routine manually to resolve such issues.

Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20230324145557.27797-1-ddrokosov@sberdevices.ru


Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>