ALSA: ASoC: Hide TLV320AIC26 configuration option for non-OpenFirwmare users

Make the visibility of the tristate conditional on having the OpenFirmware
helper code enabed so that users who can't use it don't see the visible
option. Kconfig ignores dependencies for select so other users are
unaffected.

Thanks to Takashi for the suggestion.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
index 4975d85..38a0e3b 100644
--- a/sound/soc/codecs/Kconfig
+++ b/sound/soc/codecs/Kconfig
@@ -68,7 +68,7 @@
 	depends on I2C
 
 config SND_SOC_TLV320AIC26
-	tristate "TI TLV320AIC26 Codec support"
+	tristate "TI TLV320AIC26 Codec support" if SND_SOC_OF_SIMPLE
 	depends on SPI
 
 config SND_SOC_TLV320AIC3X