regulator: qpnp-labibb-regulator: Allow configuring SOFT_START_CTL

Currently, LAB_SOFT_START_CTL and IBB_SOFT_START_CTL registers are
configured only if the IBB module was not enabled already by the
bootloader. Allow configuring them unconditionally if the device tree
parameters are specified in HLOS.

CRs-Fixed: 865268
Change-Id: I8455f40be0824cb7501279fb988ab92c7beccbb9
Signed-off-by: Ravindranath Thiyagarajan <rthiyaga@codeaurora.org>
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>