Add soc-qcom pkg, drop soc-qcom-sdm845

Turns out a lot of non-sdm845 device pkgs were depending on soc-qcom-sdm845, and this confused me greatly.

To help keep things straight forward and tidy, I basically renamed soc-qcom-sdm845 to soc-qcom and adjusted pkgs accordingly.

There doesn't seem to be any reason to keep a separate soc-qcom-sdm845 package around anymore, so I dropped it.

I also separated the sdm845 alsa-ucm-conf pkg into a new one, since this is consistent with how we package ucm for other devices.