[fsbl] add fsbl for cv181x/cv180x

Change-Id: I6809bc5016d4bc148f62be2ed3f8e928ec111f19

fsbl/lib/libtommath/bn_mp_zero.c

@@ -0,0 +1,33 @@
+#include "tommath_private.h"
+#ifdef BN_MP_ZERO_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is a library that provides multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library was designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * SPDX-License-Identifier: Unlicense
+ */
+
+/* set to zero */
+void mp_zero(mp_int *a)
+{
+   int       n;
+   mp_digit *tmp;
+
+   a->sign = MP_ZPOS;
+   a->used = 0;
+
+   tmp = a->dp;
+   for (n = 0; n < a->alloc; n++) {
+      *tmp++ = 0;
+   }
+}
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */