Use DECLARE_FLEX_ARRAY() helper in include/uapi/sound/asoc.h

[GustavoARSilva]

diff -u -p ./include/uapi/sound/asoc.h /tmp/nothing/include/uapi/sound/asoc.h
--- ./include/uapi/sound/asoc.h
+++ /tmp/nothing/include/uapi/sound/asoc.h
@@ -228,7 +228,6 @@ struct snd_soc_tplg_vendor_array {
        union {
                struct snd_soc_tplg_vendor_uuid_elem uuid[0];
                struct snd_soc_tplg_vendor_value_elem value[0];
-               struct snd_soc_tplg_vendor_string_elem string[0];
        };
 } __attribute__((packed));