regulator: lcdb: Add WA for vph_pwr_2p5_ok signal being invalid

The LCDB module does not sample the vph_pwr_2p5_ok signal if it drops
low when the module is off. It will continue with the last known
state of vph_pwr_2p5_ok which could cause a problem if vph_pwr_2p5_ok
is indeed low. Fix this by re-enabling of the module to activate
the vph_pwr_2p5_ok signal sampling.

CRs-Fixed: 1053543
Change-Id: If0950140cae12c92bb6be428b22400b492f823e4
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>