ASoC: SDCA: Update counting of SU/GE DAPM routes

ASoC: SDCA: Update counting of SU/GE DAPM routes

Device Layer Selector Unit's are controlled by a Group Entity control
rather than by the host directly. For the purposes of the ASoC class
driver the number of input routes to the SU is controlled by the number
of options within the Group Entity Selected Mode Control. ie. One valid
DAPM route for each valid route defined in the Group Entity.

Currently the code assumes that a Device Layer SU will have a number of
routes equal to the number of potential sources for the SU. ie. it
counts the routes using the SU, but then creates the routes using the
GE. However, this isn't actually true, it is perfectly allowed for the
GE to only define options for some of the potential sources of the SU.o
In such a case the number of routes return will not match those created,
leading to either an overflow of the routes array or undefined routes to
be past to the ASoC core, both of which generally lead to the sound card
failing to probe.

Update the handling for the counting of routes to count the connected
routes on the GE itself and then ignore the source routes on the SU.
This makes it match the logic generating the routes and ensuring that
both remain in sync.

Fixes: 2c8b3a8e6aa8 ("ASoC: SDCA: Create DAPM widgets and routes from DisCo")
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.dev>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://patch.msgid.link/20260225140118.402695-3-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>