ASoC: rt5640: add internal clock source support

Adding missing definitions and flags to select internal
clock source as system clock, needed for jack detection.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/codecs/rt5640.h b/sound/soc/codecs/rt5640.h
index 58b664b..90c8871 100644
--- a/sound/soc/codecs/rt5640.h
+++ b/sound/soc/codecs/rt5640.h
@@ -984,6 +984,7 @@
 #define RT5640_SCLK_SRC_SFT			14
 #define RT5640_SCLK_SRC_MCLK			(0x0 << 14)
 #define RT5640_SCLK_SRC_PLL1			(0x1 << 14)
+#define RT5640_SCLK_SRC_RCCLK			(0x2 << 14)
 #define RT5640_PLL1_SRC_MASK			(0x3 << 12)
 #define RT5640_PLL1_SRC_SFT			12
 #define RT5640_PLL1_SRC_MCLK			(0x0 << 12)