To ensure that DPCM takes into account the backend hardware limitations
when user space queries the hw_params of a device, we need to add
dpcm_merged_format, dpcm_merged_chan, and dpcm_merged_rate to the FE
dai_links.

This patch includes only stereo FE dai_links, since multi-channel FEs
may be reserved for specific purposes. Therefore, it may not be
appropriate to consider BE conditions.
Signed-off-by: Trevor Wu <trevor.wu@mediatek.com>
Link: https://lore.kernel.org/r/20230706064123.29790-1-trevor.wu@mediatek.comSigned-off-by: Mark Brown <broonie@kernel.org>