backlight: qcom-wled: Restructure the driver for WLED3

Restructure the driver to add the support for new WLED
peripherals.

Signed-off-by: Kiran Gunda <[email protected]>
Acked-by: Daniel Thompson <[email protected]>
Signed-off-by: Lee Jones <[email protected]>

Author: I-n-o-k