device-pine64-pinephone: reduce diff between upstream alsa ucm conf and ours

Upstream ALSA UCM conf still does not work exactly for us, but parts of it do. This commit incorporates those parts to reduce the diff between the two.

One of the changes is to move /usr/share/alsa/ucm2/PinePhone/* to .../ucm2/Allwinner/A64/PinePhone/* to match upstream, and to stop creating the symlink .../ucm2/conf.d/simple-card/PinePhone.conf since upstream already provides it. However this means that just upgrading device-pine64-pinephone will remove the symlink and not replace the symlink from upstream package. Users will need to run apk fix --reinstall alsa-ucm-conf to recreate it, and will not have sound until they do.

Ref: #2115