The rk_hdmi (shared functions for multiple HDMI mini-drivers) has been
using devfdt_get_addr() to read the HDMI controller's IO base address.
This will cause a failure with a live tree.
This changes the driver to use dev_read_addr() which is safe both for
flat trees and live trees.
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com> Tested-by: Klaus Goger <klaus.goger@theobroma-systems.com> Reviewed-by: Anatolij Gustschin <agust@denx.de>