common/lcd: Make lcd_dt_simplefb_configure_node use fdt_setup_simplefb_node

Change lcd_dt_simplefb_configure_node into a wrapper around the new generic
fdt_setup_simplefb_node helper function.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Simon Glass <sjg@chromium.org>