auc: fall back to 'sdcard' image

Fallback to use 'sdcard' image in case there is neither 'sysupgrade'
nor 'combined' image available.
This allows using 'auc' on targets where 'sdcard' image is also used
for sysupgrade (such as some mvebu-based devices with eMMC).

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

utils/auc/src/auc.c

@@ -1363,6 +1363,10 @@ static int select_image(struct blob_attr *images, const char *target_fstype, cha
 		ret = get_image_by_type(images, combined_type, fstype, image_name, image_sha256);
 		if (!ret)
 			return 0;
+
+		ret = get_image_by_type(images, "sdcard", fstype, image_name, image_sha256);
+		if (!ret)
+			return 0;
 	}
 
 	/* fallback to squashfs unless fstype requested explicitly */
@@ -1372,6 +1376,10 @@ static int select_image(struct blob_attr *images, const char *target_fstype, cha
 			return 0;
 
 		ret = get_image_by_type(images, combined_type, "squashfs", image_name, image_sha256);
+		if (!ret)
+			return 0;
+
+		ret = get_image_by_type(images, "sdcard", fstype, image_name, image_sha256);
 	}
 
 	return ret;