image: add IH_OS_ARM_TRUSTED_FIRMWARE for ARM Trusted Firmware

To boot on ARMv8 systems with ARM Trusted Firmware, we need to
assemble an ATF-specific parameter structure and also provide the
address of the images started by ATF (e.g. BL3-3, which may be the
full U-Boot).

To allow us to identify an ARM Trusted Firmware contained in a FIT
image, this adds the necessary definitions.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/image.c b/common/image.c
index 06fdca1..4ec4744 100644
--- a/common/image.c
+++ b/common/image.c
@@ -95,6 +95,7 @@
 
 static const table_entry_t uimage_os[] = {
 	{	IH_OS_INVALID,	"invalid",	"Invalid OS",		},
+	{       IH_OS_ARM_TRUSTED_FIRMWARE, "arm-trusted-firmware", "ARM Trusted Firmware"  },
 	{	IH_OS_LINUX,	"linux",	"Linux",		},
 #if defined(CONFIG_LYNXKDI) || defined(USE_HOSTCC)
 	{	IH_OS_LYNXOS,	"lynxos",	"LynxOS",		},
diff --git a/include/image.h b/include/image.h
index 127cfc5..e9c18ce 100644
--- a/include/image.h
+++ b/include/image.h
@@ -152,6 +152,7 @@
 	IH_OS_OSE,			/* OSE		*/
 	IH_OS_PLAN9,			/* Plan 9	*/
 	IH_OS_OPENRTOS,		/* OpenRTOS	*/
+	IH_OS_ARM_TRUSTED_FIRMWARE,     /* ARM Trusted Firmware */
 
 	IH_OS_COUNT,
 };