Remove unused variable in mpi_mul_hlp()

Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/library/bignum.c b/library/bignum.c
index 288f859..22cbffa 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -1398,7 +1398,7 @@
                   mbedtls_mpi_uint *d,
                   mbedtls_mpi_uint b )
 {
-    mbedtls_mpi_uint c = 0, t = 0;
+    mbedtls_mpi_uint c = 0; /* carry */
 
 #if defined(MULADDC_HUIT)
     for( ; i >= 8; i -= 8 )
@@ -1449,8 +1449,6 @@
     }
 #endif /* MULADDC_HUIT */
 
-    t++;
-
     while( c != 0 )
     {
         *d += c; c = ( *d < c ); d++;