Add support for U-Boot DM and DT probing. Furthermore, build the
SMC911x standalone EEPROM example only for the non-DM case, as it
is not converted yet.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>