fit: Add standalone image type handling

Just add IH_TYPE_STANDALONE to fit_get_image_type_property().

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/image-fit.c b/common/image-fit.c
index e3577e2..8c15ed1 100644
--- a/common/image-fit.c
+++ b/common/image-fit.c
@@ -1725,6 +1725,8 @@
 		return FIT_LOADABLE_PROP;
 	case IH_TYPE_FPGA:
 		return FIT_FPGA_PROP;
+	case IH_TYPE_STANDALONE:
+		return FIT_STANDALONE_PROP;
 	}
 
 	return "unknown";