uboot-imx

rockchip: rk3368: syscon: SGRF support for OF_PLATDATA

In TPL we will need to configure security in the SGRF of the RK3368.
This change adds support for the SGRF as a syscon device, so we can
retrieve its address range through the syscon API in TPL (and can
avoid having to hard-code the address).

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>