soc: renesas: r8a77990-sysc: Add workaround for 3DG-{A,B}

This patch adds workaround for 3DG-{A,B} of R-Car E3 ES1.0 because
the SoC has a restriction about the order.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>