thermal: Add support for TI LM74

LM74 is a SPI temperature sensor.

Implement a driver to read temperature from it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 8acc7d2..b5ab0fc 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -9,3 +9,4 @@
 obj-$(CONFIG_IMX_SCU_THERMAL) += imx_scu_thermal.o
 obj-$(CONFIG_TI_DRA7_THERMAL) += ti-bandgap.o
 obj-$(CONFIG_IMX_TMU) += imx_tmu.o
+obj-$(CONFIG_TI_LM74_THERMAL) += ti-lm74.o