CEC: Dump recent message history for better logging

Logging for CEC messages is disabled by default, so it is hard to debug
using bug report. Providing recent history of cec messages would be
helpful to see what happened via CEC line.

Bug: 33682018
Test: adb shell dumpsys hdmi_control
Change-Id: I476ce454418d6da8d65f520cc79d653bf96f3afd