testing/linux-postmarketos-qcom-sdm670: upgrade to 6.8.2

This is mostly a version bump to accept upstream changes in mainline Linux. The full changes since the last release can be found here.

Draft release notes

For the LPI TLMM (pin controller for audio), a missing slew memory region was ignored. This behavior is superseded by using a flag to avoid searching for the memory region.

Some patches were applied to linux-next and picked from there.

Audio, bluetooth, camera, display, GPU, USB, I2C, eMMC, modem, video acceleration, and haptics should work and be slightly broken like before.