ASoC: SOF: mediatek: Commonize duplicated functions

In order to reduce duplication, move the ADSP mailbox callbacks
handle_reply(), handle_request(), and other common SOF callbacks
send_msg(), get_bar_index(), pcm_hw_params() and pcm_pointer()
to the mtk-adsp-common.c file.

This cleanup brings no functional differences.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patch.msgid.link/20250320115300.137410-1-angelogioacchino.delregno@collabora.com


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