Merge pull request #5928 from dgarske/zd15388

Fixes SP math all build issue with small-stack and no hardening

wolfcrypt/src/sp_int.c

@@ -12706,7 +12706,11 @@ static int _sp_exptmod_base_2(const sp_int* e, int digits, const sp_int* m,
     sp_print(r, "rme");
 #endif
 
+#ifndef WC_NO_HARDEN
     FREE_SP_INT_ARRAY(d, NULL);
+#else
+    FREE_SP_INT(tr, m->used * 2 + 1);
+#endif
     return err;
 }
 #endif