Remove unused parameter

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
diff --git a/library/bignum_core.c b/library/bignum_core.c
index 9adc4ef..7074a09 100644
--- a/library/bignum_core.c
+++ b/library/bignum_core.c
@@ -178,15 +178,14 @@
 }
 
 void mbedtls_mpi_core_cond_swap( mbedtls_mpi_uint *X,
-                                 size_t X_limbs,
                                  mbedtls_mpi_uint *Y,
-                                 size_t Y_limbs,
+                                 size_t limbs,
                                  unsigned char swap )
 {
     /* all-bits 1 if swap is 1, all-bits 0 if swap is 0 */
     mbedtls_mpi_uint limb_mask = mbedtls_ct_mpi_uint_mask( swap );
 
-    for( size_t i = 0; i < X_limbs; i++ )
+    for( size_t i = 0; i < limbs; i++ )
     {
         mbedtls_mpi_uint tmp = X[i];
         X[i] = ( X[i] & ~limb_mask ) | ( Y[i] & limb_mask );