This patch enables the DM support for the SPI driver and the
SPI NOR flash chips. Some MVEBU boards boot from SPI NOR, so
adding the aliases and enabling CONFIG_DM_SEQ_ALIAS is needed
here.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Luka Perkov <luka.perkov@sartura.hr>
Cc: Dirk Eibach <dirk.eibach@gdsys.cc>
Cc: Simon Glass <sjg@chromium.org>