sdm: Fix to defer the first power on to first commit

Defer the first power on to first commit and enable
the pending vsync after the first commit.

Bug: 142222452
Bug: 143850051
Test: 1. No black screen during boot animation
      2. Boot to home without flicker
Change-Id: Id442e7ac7df38a14f66904696e5a668733bac98b
8 files changed