rockchip: rk3288: syscon_rk3288: store syscon platdata in regmap

The Rockchip SoC rk3288 has 2 types of device trees floating around.
A 64bit reg size when synced from Linux and a 32bit for U-boot.
A pre-probe function in the syscon class driver assumes only 32bit.
For other odd reg structures the regmap must be defined in the individual
syscon driver. Store rk3288 platdata in a regmap before pre-probe
during bind.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>