regulator: qpnp-amoled: Prevent premature AOD exit configuration

Currently, when the display driver notifies to exit AOD mode,
AOD configuration is attempted after polling for VREG_OK high.
On some AMOLED panels, SWIRE can pulse for a shorter period in
AOD mode which can cause AOD exit configuration to be made
prematurely. Prevent this by polling for VREG_OK for another
80 ms after it is found to be set high. If it goes low, then it
is an intermittent SWIRE pulse. Poll VREG_OK for another 100 ms
for a valid SWIRE pulse which if fails would timeout as before.

Change-Id: Ib480e15206ce941c03fbecd751b88168613d44c1
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>