ASoC: SOF: sof-audio: Avoid -Wflex-array-member-not-at-end warnings

-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

Move the conflicting declaration to the end of the structure. Notice
that `struct snd_sof_pcm` ends in a flexible-array member through
`struct snd_soc_tplg_pcm` -> `struct snd_soc_tplg_private`.

Whith this, fix the following warnings:
sound/soc/sof/sof-audio.h:350:33: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
./include/trace/events/../../../sound/soc/sof/sof-audio.h:350:33: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
sound/soc/amd/../sof/amd/../sof-audio.h:350:33: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
sound/soc/sof/amd/../sof-audio.h:350:33: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
sound/soc/sof/intel/../sof-audio.h:350:33: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
sound/soc/sof/mediatek/mt8186/../../sof-audio.h:350:33: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
sound/soc/sof/mediatek/mt8195/../../sof-audio.h:350:33: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://patch.msgid.link/ZrDvt6eyeFyajq6l@cute


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