Align signature_algorithms extension name

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index a8b1e7d..a137e43 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -239,9 +239,9 @@
  * This needs to be done at a later stage.
  *
  */
-static int ssl_parse_signature_algorithms_ext( mbedtls_ssl_context *ssl,
-                                               const unsigned char *buf,
-                                               size_t len )
+static int ssl_parse_sig_alg_ext( mbedtls_ssl_context *ssl,
+                                  const unsigned char *buf,
+                                  size_t len )
 {
     size_t sig_alg_list_size;
 
@@ -1674,7 +1674,7 @@
             case MBEDTLS_TLS_EXT_SIG_ALG:
                 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) );
 
-                ret = ssl_parse_signature_algorithms_ext( ssl, ext + 4, ext_size );
+                ret = ssl_parse_sig_alg_ext( ssl, ext + 4, ext_size );
                 if( ret != 0 )
                     return( ret );