Fix whitespace issue spotted in review

Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>
diff --git a/library/bignum.c b/library/bignum.c
index f30df2b..d33f07c 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -895,7 +895,7 @@
 
     mbedtls_mpi_uint *p = X->p;
 
-    mbedtls_mpi_uint c = mbedtls_mpi_core_add( p, p, B->p, j);
+    mbedtls_mpi_uint c = mbedtls_mpi_core_add( p, p, B->p, j );
 
     p += j;