libhwc2.1: postpone vsync callback until get vsync from driver

If we don't know the last hw vsync timestamp and fail to get it from
driver, postpone the vsync callback until we can get real value from
the hardware to avoid report incorrect hw vsync timestamp. Also send
wake up signal to driver while enabling vsync.

Bug: 189173278
Bug: 191386940
Test: perfetto trace
Change-Id: I2f52f067838540df562dc8bb6e1165ee59760ec1
7 files changed