ASoC: simple-card: Fill in driver name

alsa-ucm groups by driver name so fill that in as well. Otherwise the
presented information is redundant and doesn't reflect the used
driver. We can't just use 'asoc-simple-card' since the driver name is
restricted to 15 characters.

Before:

 # cat /proc/asound/cards
 0 [Devkit         ]: Librem_5_Devkit - Librem 5 Devkit
                      Librem 5 Devkit
After:

 0 [Devkit         ]: simple-card - Librem 5 Devkit
                      Librem 5 Devkit
Signed-off-by: Guido Günther <agx@sigxcpu.org>
Link: https://lore.kernel.org/r/YNGe3akAntQi8qJD@qwark.sigxcpu.orgSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/generic/simple-card.c

@@ -621,6 +621,7 @@ static int asoc_simple_probe(struct platform_device *pdev)
 	card->owner		= THIS_MODULE;
 	card->dev		= dev;
 	card->probe		= simple_soc_probe;
+	card->driver_name       = "simple-card";
 
 	li = devm_kzalloc(dev, sizeof(*li), GFP_KERNEL);
 	if (!li)