sdm: Use retire fence wait in PowerOff API

DAL should wait on retire fence to make sure that H/W Power transition
gets completed in SetPowerMode call from Surfaceflinger.

Waiting on release fence will lead to fence timeout on video mode, DP
display devices.

Change-Id: Icb2ba48b2150181c766611c074884450bb9d83f1
CRs-Fixed: 2520035
1 file changed