backlight: qcom-spmi-wled: Add low dimming workaround for WLED5

In PM8150L, when the brightness is set to low levels (< 1%) higher
latencies are observed when the module is enabled. As per the
hardware recommendation, add a workaround as following:

- Disable sample and hold configuration
- Enable module
- Wait for 5 ms
- Enable sample and hold configuration

Currently, this workaround is enabled only when CABC is disabled.

CRs-Fixed: 2185979
Change-Id: I23b125e65d1a0d20d0fb0620e17bc78e7778f16d
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>