Add missing dependencies

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 2b7f447..39daaf7 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -6512,10 +6512,10 @@
                            unsigned char *dstbuf, size_t dlen );
 static tls_prf_fn ssl_tls12prf_from_cs( int ciphersuite_id )
 {
-#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)
     const mbedtls_ssl_ciphersuite_t * const ciphersuite_info =
          mbedtls_ssl_ciphersuite_from_id( ciphersuite_id );
 
+    #if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)
     if( ciphersuite_info->mac == MBEDTLS_MD_SHA384 )
         return( tls_prf_sha384 );
     else