Removes mode param from mbedtls_rsa_pkcs1_sign

Commit removes the mode parameter from
mbedtls_rsa_pkcs1_sign and progagates the
change to all relevant parts of the codebase.

Signed-off-by: Thomas Daubney <thomas.daubney@arm.com>
diff --git a/programs/pkey/dh_server.c b/programs/pkey/dh_server.c
index dccf095..63df77e 100644
--- a/programs/pkey/dh_server.c
+++ b/programs/pkey/dh_server.c
@@ -229,7 +229,7 @@
     buf[n    ] = (unsigned char)( rsa.len >> 8 );
     buf[n + 1] = (unsigned char)( rsa.len      );
 
-    if( ( ret = mbedtls_rsa_pkcs1_sign( &rsa, NULL, NULL, MBEDTLS_RSA_PRIVATE, MBEDTLS_MD_SHA256,
+    if( ( ret = mbedtls_rsa_pkcs1_sign( &rsa, NULL, NULL, MBEDTLS_MD_SHA256,
                                 0, hash, buf + n + 2 ) ) != 0 )
     {
         mbedtls_printf( " failed\n  ! mbedtls_rsa_pkcs1_sign returned %d\n\n", ret );