livetree: fix off-by-one in propval_cell_n() bounds check

Signed-off-by: Johannes Beisswenger <johannes.beisswenger@cetitec.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

livetree.c

@@ -441,7 +441,7 @@ cell_t propval_cell(struct property *prop)
 
 cell_t propval_cell_n(struct property *prop, unsigned int n)
 {
-	assert(prop->val.len / sizeof(cell_t) >= n);
+	assert(prop->val.len / sizeof(cell_t) > n);
 	return fdt32_to_cpu(*((fdt32_t *)prop->val.val + n));
 }