[][Add Proslic SI3218x audio codec driver]

[Description]
Add Proslic SI3218x audio codec driver

[Release-log]
N/A

Change-Id: I30edf714fda413b220b6a0f3e301a7bc3f899c08
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/5396999
40 files changed