[][kernel][common][audio][Remove mt79xx audio driver]

[Description]
Remove mt79xx audio driver.
Filogic series will use backport mt7986 audio driver from kernel 6.7.

[Release-log]
N/A

Change-Id: Idf5c8d3412638175d498445d3f3bf7df69fa6a92
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/8265916
10 files changed