ASoC: madera: Add support for using MCLK3

Some Madera CODECs have a third MCLK pin allow this to be sourced for
the FLLs and system clocks.
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20191001135700.31017-1-ckeepax@opensource.cirrus.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/madera.h

@@ -27,6 +27,7 @@
 #define MADERA_FLL_SRC_NONE		-1
 #define MADERA_FLL_SRC_MCLK1		0
 #define MADERA_FLL_SRC_MCLK2		1
+#define MADERA_FLL_SRC_MCLK3		2
 #define MADERA_FLL_SRC_SLIMCLK		3
 #define MADERA_FLL_SRC_FLL1		4
 #define MADERA_FLL_SRC_FLL2		5
@@ -51,6 +52,7 @@
 
 #define MADERA_CLK_SRC_MCLK1		0x0
 #define MADERA_CLK_SRC_MCLK2		0x1
+#define MADERA_CLK_SRC_MCLK3		0x2
 #define MADERA_CLK_SRC_FLL1		0x4
 #define MADERA_CLK_SRC_FLL2		0x5
 #define MADERA_CLK_SRC_FLL3		0x6