backlight: qcom-spmi-wled: update check for OVP fault in probe

When OVP fault is detected during WLED driver probe, SW first needs to
confirm that OVP event is sustained over a minimum time duration
before fixing it. After reading fault status and seeing OVP is set,
add time delay equal to OVP_INT_TIMER value, and ensure OVP fault
is still seen, before running auto calibration algorithm.

Change-Id: I4fbc75fa1f63af53fe2e1b5298e0e277cc8a74b8
Signed-off-by: Jishnu Prakash <jprakash@codeaurora.org>