The PMI8998 PMIC has a WLED backlight controller, which is used on
most MSM8998 and SDM845 based devices: add a base configuration for
it and keep it disabled.
This contains only the PMIC specific configuration that does not
change across boards; parameters like number of strings, OVP and
current limits are product specific and shall be specified in the
product DT in order to achieve functionality.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxxx>