Add Atmel I2C tpm

Add support for Atmel TPM devices with two wire interface.

Signed-off-by: Dirk Eibach <dirk.eibach@gdsys.cc>
Signed-off-by: Reinhard Pfau <reinhard.pfau@gdsys.cc>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Andy Fleming <afleming@freescale.com>
diff --git a/README b/README
index 3941725..bcfffc3 100644
--- a/README
+++ b/README
@@ -1238,6 +1238,9 @@
 			CONFIG_TPM_TIS_I2C_BURST_LIMITATION
 			Define the burst count bytes upper limit
 
+		CONFIG_TPM_ATMEL_TWI
+		Support for Atmel TWI TPM device. Requires I2C support.
+
 		CONFIG_TPM_TIS_LPC
 		Support for generic parallel port TPM devices. Only one device
 		per system is supported at this time.