leds: qpnp-wled: avoid false ovp on module enable

False ovp (over voltage protection) can be triggered
when the module is enabled. Avoid this scenario by
disabling the ovp before enabling the module. Enable
ovp after the module is enabled.

Change-Id: Icaa390b61ae2b09e21b10b801b8e22b0e6da5c3d
Signed-off-by: Mohan Pallaka <mpallaka@codeaurora.org>