Remove superfluous brackets

Signed-off-by: Thomas Daubney <thomas.daubney@arm.com>
diff --git a/library/aes.c b/library/aes.c
index ae883b2..72e2c57 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -508,7 +508,7 @@
  * Note that the offset is in units of elements of buf, i.e. 32-bit words,
  * i.e. an offset of 1 means 4 bytes and so on.
  */
-#if (defined(MBEDTLS_AESNI_C) && MBEDTLS_AESNI_HAVE_CODE == 2)
+#if defined(MBEDTLS_AESNI_C) && MBEDTLS_AESNI_HAVE_CODE == 2
 #define MAY_NEED_TO_ALIGN
 #endif