schema tree BUGFIX last array value size 1B is not enough

Instead, use pointer size as in these arrays the first attribute
of the structure is always a string, which will not be 0 if filled
(but could have been 0 if truncated to 1B).
diff --git a/src/tree_schema.h b/src/tree_schema.h
index 8aa9cb4..6266427 100644
--- a/src/tree_schema.h
+++ b/src/tree_schema.h
@@ -32,7 +32,7 @@
  * @param[in] ARRAY Array to go through
  * @param[out] ITER Numeric iterator storing available indexes of the ARRAY
  */
-#define LY_ARRAY_FOR(ARRAY, ITER) for (ITER = 0; (ARRAY) && *((uint8_t *)((ARRAY) + ITER)); ++ITER)
+#define LY_ARRAY_FOR(ARRAY, ITER) for (ITER = 0; (ARRAY) && *((void **)((ARRAY) + ITER)); ++ITER)
 
 /**
  * @brief Macro to iterate via all sibling elements without affecting the list itself