ASoC: SOF: tokens: add token for Mediatek AFE

Add the definition for Mediatek audio front end(AFE) tokens,include
AFE sampling rate, channels, and format.

Signed-off-by: YC Hung <[e-mail]>
Reviewed-by: Péter Ujfalusi <[e-mail]>
Reviewed-by: Pierre-Louis Bossart <[e-mail]>
Reviewed-by: Ranjani Sridharan <[e-mail]>
Reviewed-by: Kai Vehmanen <[e-mail]>
Reviewed-by: Guennadi Liakhovetski <[e-mail]>
Reviewed-by: Daniel Baluta <[e-mail]>
Signed-off-by: Daniel Baluta <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

include/uapi/sound/sof/tokens.h

···
 #define SOF_TKN_INTEL_HDA_RATE			1500
 #define SOF_TKN_INTEL_HDA_CH			1501
 
+/* AFE */
+#define SOF_TKN_MEDIATEK_AFE_RATE		1600
+#define SOF_TKN_MEDIATEK_AFE_CH			1601
+#define SOF_TKN_MEDIATEK_AFE_FORMAT		1602
+
 #endif