ARM: dts: rockchip: add space after &grf on rk3188

Fix layout by adding a space after &grf.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Link: https://lore.kernel.org/r/20210709103134.1750-1-jbx6244@gmail.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>