Add support for the Pixel 6 emeter GPU channel

Created by: mrkajetanp

This PR adds support for the Pixel 6 emeter GPU channel in Lisa. It involves expanding the lisa sched_tp module to support passing private data down the parser chain. This functionality is then used to distinguish between the two different power meter devices when outputting trace events. Then, the pixel6_emeter parser logic is extended to parse both the power meter files (device0 and device1), covering all the channels in the process. Finally, a GPU power channel is included in Lisa's pixel6 analysis to make use of the newly added functionality in trace analysis.