DM: thermal: Add imx thermal DM driver

Add a new thermal uclass for thermal sensor and implement the imx
thermal driver basing on this uclass.

Signed-off-by: Ye.Li <B37916@freescale.com>
Acked-by: Stefano Babic <sbabic@denx.de>
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index a8944c9..202f59b 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -28,6 +28,7 @@
 	UCLASS_SPI_GENERIC,	/* Generic SPI flash target */
 	UCLASS_SPI_FLASH,	/* SPI flash */
 	UCLASS_CROS_EC,	/* Chrome OS EC */
+	UCLASS_THERMAL,		/* Thermal sensor */
 
 	UCLASS_COUNT,
 	UCLASS_INVALID = -1,