dm: core: make simple-bus compatible to simple-mfd

Simple MFD devices can bind children without special bus configuration.
Like Linux, let's handle "simple-mfd" in the same way as "simple-bus".

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>
1 file changed