Change crypto clients to use rpc_caller_session

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: I6c370e8dc14f2262a2502995f655888a80d69c7b
diff --git a/components/service/common/serializer/protobuf/pb_helper.h b/components/service/common/serializer/protobuf/pb_helper.h
index 1f109b0..61c0ae9 100644
--- a/components/service/common/serializer/protobuf/pb_helper.h
+++ b/components/service/common/serializer/protobuf/pb_helper.h
@@ -13,6 +13,8 @@
 extern "C" {
 #endif
 
+#define PB_PACKET_LENGTH(payload_length)	((payload_length) + 16)
+
 /* Returns an initialised pb_callback_t structure for encoding a variable length byte array */
 extern pb_callback_t pb_out_byte_array(const pb_bytes_array_t *byte_array);