device-pine64-pinebookpro: drop ALSA UCM configs

alsa-ucm-conf was upgraded on the 3.16 stable branch, so we need to backport this for the Pinebook Pro device package to not conflict with alsa-ucm-conf: https://gitlab.alpinelinux.org/alpine/aports/-/commit/77a0400641905326ea23db48a3b9d4446a3013fe

Would be nice to have someone with a Pinebook Pro test this before we merge it (I don't have one), but I guess it should be fine given that this has been tested on edge already.