qcom: spmi-wled: Add auto-calibration logic support

The auto-calibration algorithm checks if the current WLED sink
configuration is valid. It tries enabling every sink and checks
if the OVP fault is observed. Based on this information it
detects and enables the valid sink configuration. Auto calibration
will be triggered when the OVP fault interrupts are seen frequently
thereby it tries to fix the sink configuration.

Change-Id: I835d7b9883b1fcf4d800d3bd480eab793441ef1b
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>