vboot: Do not use hashed-strings offset

The hashed-strings signature property includes two uint32_t values.
The first is unneeded as there should never be a start offset into the
strings region. The second, the size, is needed because the added
signature node appends to this region.

See tools/image-host.c, where a static 0 value is used for the offset.

Signed-off-by: Teddy Reed <teddy.reed@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

tools/image-host.c

@@ -135,6 +135,7 @@ static int fit_image_write_sig(void *fit, int noffset, uint8_t *value,
 
 		ret = fdt_setprop(fit, noffset, "hashed-nodes",
 				   region_prop, region_proplen);
+		/* This is a legacy offset, it is unused, and must remain 0. */
 		strdata[0] = 0;
 		strdata[1] = cpu_to_fdt32(string_size);
 		if (!ret) {