SF: Store DeviceProductInfo in DisplayDevice

When a new display is connected we query the display
identification data, parse the EDID and store it in
DisplayDevice for future use. This saves an unnecessary IPC
to HWC when SurfaceFlinger::getDisplayInfo() is called.

Bug: 149075047
Test: 1. flash a device
      2. boot a device connected to a display
      3. Check for sensible DeviceProductInfo:
         adb shell dumpsys SurfaceFlinger | grep deviceProductInfo
         adb shell dumpsys display | grep deviceProductInfo
      4. reboot without a display
      5. Check that  DeviceProductInfo is empty / null in
         adb shell dumpsys SurfaceFlinger | grep deviceProductInfo
         adb shell dumpsys display | grep deviceProductInfo
Change-Id: I35b6b3869eb740dd90913c9d3095fdc591b5ba3c