ASoC: ab8500: Inform SoC Core that we have our own I/O arrangements

If codec->control_data is not populated SoC Core assumes we want to
use regmap, which fails catastrophically, as we don't have one:

Unable to handle kernel NULL pointer dereference at virtual address 00000080
pgd = c0004000
[00000080] *pgd=00000000
Internal error: Oops: 17 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 1    Not tainted  (3.5.0-rc6-00884-g0b2419e-dirty #130)
PC is at regmap_read+0x10/0x5c
LR is at hw_read+0x80/0x90
pc : [<c01a91b8>]    lr : [<c0216804>]    psr: 60000013
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/ab8500-codec.c

@@ -2406,6 +2406,10 @@ static int ab8500_codec_probe(struct snd_soc_codec *codec)
 
 	/* Setup AB8500 according to board-settings */
 	pdata = (struct ab8500_platform_data *)dev_get_platdata(dev->parent);
+
+	/* Inform SoC Core that we have our own I/O arrangements. */
+	codec->control_data = (void *)true;
+
 	status = ab8500_audio_setup_mics(codec, &pdata->codec->amics);
 	if (status < 0) {
 		pr_err("%s: Failed to setup mics (%d)!\n", __func__, status);