This DT property allows marking flash partition that Linux should use as
a root device. It's useful for devices that don't use U-Boot and cmdline
parser for partitioning. It may be used with "fixed-partitions" or some
dynamic partitioning based on flash content.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
(cherry picked from commit d33e49857e)
