ASoC: pxa: TTC DKB audio needs I2C

The missing dependency can lead to build errors, so
make it explicit in Kconfig.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Xia Kaixu <kaixu.xia@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/pxa/Kconfig

@@ -140,7 +140,7 @@ config SND_PXA910_SOC
 
 config SND_SOC_TTC_DKB
 	bool "SoC Audio support for TTC DKB"
-	depends on SND_PXA910_SOC && MACH_TTC_DKB
+	depends on SND_PXA910_SOC && MACH_TTC_DKB && I2C=y
 	select PXA_SSP
 	select SND_PXA_SOC_SSP
 	select SND_MMP_SOC