ASoC: intel: sof_sdw: Move amp_num initialisation to mc_probe

ASoC: intel: sof_sdw: Move amp_num initialisation to mc_probe

The amp_num member of the info struct is zeroed at the start of
sof_card_dai_links_create, but then summed in mc_probe after
sof_card_dai_links_create is called. It is a little clearer to hoist the
initialisation out of sof_card_dai_links_create so it is on the same
level as the summation.

Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20230731214257.444605-18-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>