Change code for styles and comments .etc

Remove useless code in union.
Rename functions and parameters.
Move definitions into othe files.

Signed-off-by: XiaokangQian <xiaokang.qian@arm.com>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 508a5e3..fba8f8f 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -605,6 +605,8 @@
 
 #define MBEDTLS_PREMASTER_SIZE     sizeof( union mbedtls_ssl_premaster_secret )
 
+#define MBEDTLS_TLS1_3_MD_MAX_SIZE         MBEDTLS_MD_MAX_SIZE
+
 /* Length in number of bytes of the TLS sequence number */
 #define MBEDTLS_SSL_SEQUENCE_NUMBER_LEN 8
 
@@ -1052,10 +1054,10 @@
 
 typedef struct
 {
-    unsigned char client_application_traffic_secret_N[ MBEDTLS_MD_MAX_SIZE ];
-    unsigned char server_application_traffic_secret_N[ MBEDTLS_MD_MAX_SIZE ];
-    unsigned char exporter_master_secret             [ MBEDTLS_MD_MAX_SIZE ];
-    unsigned char resumption_master_secret           [ MBEDTLS_MD_MAX_SIZE ];
+    unsigned char client_application_traffic_secret_N[ MBEDTLS_TLS1_3_MD_MAX_SIZE ];
+    unsigned char server_application_traffic_secret_N[ MBEDTLS_TLS1_3_MD_MAX_SIZE ];
+    unsigned char exporter_master_secret             [ MBEDTLS_TLS1_3_MD_MAX_SIZE ];
+    unsigned char resumption_master_secret           [ MBEDTLS_TLS1_3_MD_MAX_SIZE ];
 } mbedtls_ssl_tls1_3_application_secrets;
 
 #if defined(MBEDTLS_SSL_DTLS_SRTP)