dm: tpm: Add Driver Model support for tpm_atmel_twi driver

tpm_atmel_twi can fit perfectly to the new UCLASS_TPM class.

Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/tpm/Kconfig b/drivers/tpm/Kconfig
index dacb847..ff2cdbe 100644
--- a/drivers/tpm/Kconfig
+++ b/drivers/tpm/Kconfig
@@ -24,7 +24,7 @@
 
 config TPM_ATMEL_TWI
 	bool "Enable Atmel TWI TPM device driver"
-	depends on TPM
+	depends on TPM && DM_I2C
 	help
 	  This driver supports an Atmel TPM device connected on the I2C bus.
 	  The usual tpm operations and the 'tpm' command can be used to talk