[fsbl] add fsbl for cv181x/cv180x

Change-Id: I6809bc5016d4bc148f62be2ed3f8e928ec111f19

fsbl/lib/libtommath/bn_mp_n_root.c

@@ -0,0 +1,27 @@
+#include "tommath_private.h"
+#ifdef BN_MP_N_ROOT_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
+ */
+
+/* wrapper function for mp_n_root_ex()
+ * computes c = (a)**(1/b) such that (c)**b <= a and (c+1)**b > a
+ */
+int mp_n_root(const mp_int *a, mp_digit b, mp_int *c)
+{
+   return mp_n_root_ex(a, b, c, 0);
+}
+
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */