drivers/ddr/fsl: Add 3DS RDIMM support

On top of RDIMM support, add new register calculation to support
3DS RDIMMs. Only symmetrical 3DS is supported at this time.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/include/fsl_ddr_sdram.h b/include/fsl_ddr_sdram.h
index de7ef9b..d4275e6 100644
--- a/include/fsl_ddr_sdram.h
+++ b/include/fsl_ddr_sdram.h
@@ -1,5 +1,6 @@
 /*
- * Copyright 2008-2014 Freescale Semiconductor, Inc.
+ * Copyright 2008-2016 Freescale Semiconductor, Inc.
+ * Copyright 2017-2018 NXP Semiconductor
  *
  * SPDX-License-Identifier:	GPL-2.0
  */
@@ -366,6 +367,7 @@
 	unsigned int quad_rank_present;
 	unsigned int ap_en;	/* address parity enable for RDIMM/DDR4-UDIMM */
 	unsigned int x4_en;	/* enable x4 devices */
+	unsigned int package_3ds;
 
 	/* Global Timing Parameters */
 	unsigned int cas_latency_override;