splash: add support for loading splash from a FIT image

Enable support for loading a splash image from within a FIT image.
The image is assumed to be generated with mkimage -E flag to hold
the data external to the FIT.

Signed-off-by: Tomas Melin <tomas.melin@vaisala.com>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>
diff --git a/include/image.h b/include/image.h
index 0537678..ad82fda 100644
--- a/include/image.h
+++ b/include/image.h
@@ -872,6 +872,8 @@
 
 /* image node */
 #define FIT_DATA_PROP		"data"
+#define FIT_DATA_OFFSET_PROP	"data-offset"
+#define FIT_DATA_SIZE_PROP	"data-size"
 #define FIT_TIMESTAMP_PROP	"timestamp"
 #define FIT_DESC_PROP		"description"
 #define FIT_ARCH_PROP		"arch"
@@ -950,6 +952,8 @@
 int fit_image_get_entry(const void *fit, int noffset, ulong *entry);
 int fit_image_get_data(const void *fit, int noffset,
 				const void **data, size_t *size);
+int fit_image_get_data_offset(const void *fit, int noffset, int *data_offset);
+int fit_image_get_data_size(const void *fit, int noffset, int *data_size);
 
 int fit_image_hash_get_algo(const void *fit, int noffset, char **algo);
 int fit_image_hash_get_value(const void *fit, int noffset, uint8_t **value,
diff --git a/include/splash.h b/include/splash.h
index 136eac7..228aff4 100644
--- a/include/splash.h
+++ b/include/splash.h
@@ -33,8 +33,9 @@
 };
 
 enum splash_flags {
-	SPLASH_STORAGE_RAW,
-	SPLASH_STORAGE_FS,
+	SPLASH_STORAGE_RAW, /* Stored in raw memory */
+	SPLASH_STORAGE_FS,  /* Stored within a file system */
+	SPLASH_STORAGE_FIT, /* Stored inside a FIT image */
 };
 
 struct splash_location {