Mark the PRR as u-boot,dm-pre-reloc in all Gen3 board DTs as it is
needed very early and turn on the CONFIG_SYSCON to allow the PRR
driver to bind as a syscon uclass.
Signed-off-by: NMarek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>