regulator: qpnp-labibb: modify IBB_SPARE_CTL setting during TTW mode exit

Currently for PMI8996, IBB_SPARE_CTL is configured to slower PFET turn off
while exiting out of TTW mode. As per the hardware documentation, this
setting needs to be modified to faster PFET turn off for both PMI8996,
PMI8994 and PMI8950. Modify it to improve IBB efficiency.

CRs-Fixed: 966167
Change-Id: I0693eb275eeab5c349b455da31a96ba6dbeb4cf9
Signed-off-by: Harry Yang <harryy@codeaurora.org>