Fix code style nit

Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>
diff --git a/library/aes.c b/library/aes.c
index 414c42c..f08a21f 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -1005,7 +1005,7 @@
  */
 static void aes_maybe_realign(mbedtls_aes_context *ctx)
 {
-    unsigned current_offset = (unsigned)(ctx->rk - ctx->buf);
+    unsigned current_offset = (unsigned) (ctx->rk - ctx->buf);
     unsigned new_offset = mbedtls_aes_rk_offset(ctx->buf);
     if (new_offset != current_offset) {
         memmove(ctx->buf + new_offset,     // new address