libtommath: remove unnecessary comparison

As pointed out by Steffen Jaeckel [https://github.com/sjaeckel],
within bn_mp_prime_next_prime() t <= PRIME_SIZE as per the check
at the top of the function.  Remove the unnecessary comparison in
a for loop conditional.

Change-Id: I868bee1a7a019e0ab06bf2b81cc71cf66ca9acff

lib/hcrypto/libtommath/bn_mp_prime_next_prime.c

@@ -142,7 +142,7 @@ int mp_prime_next_prime(mp_int *a, int t, int bbs_style)
       }
 
       /* is this prime? */
-      for (x = 0; x < t && x < PRIME_SIZE; x++) {
+      for (x = 0; x < t; x++) {
           mp_set(&b, ltm_prime_tab[x]);
           if ((err = mp_prime_miller_rabin(a, &b, &res)) != MP_OKAY) {
              goto LBL_ERR;