Implement DM driver for the Renesas PRR into RCar cpu info and convert
all users with DM and OF enabled to this new driver. This means all of
the boards with DM and OF enabled can fetch PRR address from DT, which
is useful on ie. V3M which has different PRR address than the rest of
Gen3 SoCs.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>