Add logging to content inflation pipeline

Use new LogBuffer to add more logging to content inflation classes,
namely NotifBindPipeline and RowContentBindStage to make our debugging
lives easier.

Test: adb shell settings put global systemui/buffer/NotifLog2 debug
Observe new logs in logcat
Change-Id: Ia4232c2586bab4a766d9900b56d3aface512f29f