ASoC: wm8960: Depends on I2C

Now that this is directly user selectable it needs to care about its
dependencies.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
index 196101b..3ebf29b 100644
--- a/sound/soc/codecs/Kconfig
+++ b/sound/soc/codecs/Kconfig
@@ -910,6 +910,7 @@
 
 config SND_SOC_WM8960
 	tristate "Wolfson Microelectronics WM8960 CODEC"
+	depends on I2C
 
 config SND_SOC_WM8961
 	tristate