ASoC: Intel: avs: Silence false-positive memcpy() warnings

Commit df8fc4e9 ("kbuild: Enable -fstrict-flex-arrays=3") enforced
strict flex array declarations. This generates false-positive in form of:
"memcpy: detected field-spanning write". Avoid it by utilizing the
DECLARE_FLEX_ARRAY() macro.

Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://msgid.link/r/20240405090929.1184068-4-cezary.rojewski@intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>