ASoC: core: Try to use regmap if the driver doesn't set up any I/O

Since most new drivers are expected to use regmap and since frequently the
only thing we need to do in the CODEC probe function is configure the I/O
try to initialise the register I/O using regmap if the driver hasn't done
so after probe().

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>

sound/soc/soc-core.c

@@ -1095,6 +1095,10 @@ static int soc_probe_codec(struct snd_soc_card *card,
 		}
 	}
 
+	/* If the driver didn't set I/O up try regmap */
+	if (!codec->control_data)
+		snd_soc_codec_set_cache_io(codec, 0, 0, SND_SOC_REGMAP);
+
 	if (driver->controls)
 		snd_soc_add_codec_controls(codec, driver->controls,
 				     driver->num_controls);