fsl-ddr: use the 1T timing as default configuration

For light loaded system, we use the 1T timing to gain better
memory performance, but for some heavily loaded system,
you have to add the 2T timing options to board files.

Signed-off-by: Dave Liu <daveliu@freescale.com>
Acked-by: Andy Fleming <afleming@freescale.com>

board/freescale/mpc8540ads/ddr.c

@@ -65,6 +65,9 @@ void fsl_ddr_board_options(memctl_options_t *popts,
 	 */
 	popts->write_data_delay = 3;
 
+	/* 2T timing enable */
+	popts->twoT_en = 1;
+
 	/*
 	 * Factors to consider for half-strength driver enable:
 	 *	- number of DIMMs installed

board/freescale/mpc8544ds/ddr.c

@@ -75,6 +75,9 @@ void fsl_ddr_board_options(memctl_options_t *popts,
 	 */
 	popts->write_data_delay = 3;
 
+	/* 2T timing enable */
+	popts->twoT_en = 1;
+
 	/*
 	 * Factors to consider for half-strength driver enable:
 	 *	- number of DIMMs installed

board/freescale/mpc8560ads/ddr.c

@@ -65,6 +65,9 @@ void fsl_ddr_board_options(memctl_options_t *popts,
 	 */
 	popts->write_data_delay = 3;
 
+	/* 2T timing enable */
+	popts->twoT_en = 1;
+
 	/*
 	 * Factors to consider for half-strength driver enable:
 	 *	- number of DIMMs installed

board/freescale/mpc8610hpcd/ddr.c

@@ -74,6 +74,9 @@ void fsl_ddr_board_options(memctl_options_t *popts,
 	 */
 	popts->write_data_delay = 3;
 
+	/* 2T timing enable */
+	popts->twoT_en = 1;
+
 	/*
 	 * Factors to consider for half-strength driver enable:
 	 *	- number of DIMMs installed

board/freescale/mpc8641hpcn/ddr.c

@@ -162,4 +162,6 @@ void fsl_ddr_board_options(memctl_options_t *popts,
 		}
 	}
 
+	/* 2T timing enable */
+	popts->twoT_en = 1;
 }

board/stxgp3/ddr.c

@@ -65,6 +65,9 @@ void fsl_ddr_board_options(memctl_options_t *popts,
 	 */
 	popts->write_data_delay = 3;
 
+	/* 2T timing enable */
+	popts->twoT_en = 1;
+
 	/*
 	 * Factors to consider for half-strength driver enable:
 	 *	- number of DIMMs installed

board/stxssa/ddr.c

@@ -65,6 +65,9 @@ void fsl_ddr_board_options(memctl_options_t *popts,
 	 */
 	popts->write_data_delay = 3;
 
+	/* 2T timing enable */
+	popts->twoT_en = 1;
+
 	/*
 	 * Factors to consider for half-strength driver enable:
 	 *	- number of DIMMs installed

cpu/mpc8xxx/ddr/options.c

@@ -142,7 +142,7 @@ unsigned int populate_memctl_options(int all_DIMMs_registered,
 	 *	- number of components, number of active ranks
 	 *	- how much time you want to spend playing around
 	 */
-	popts->twoT_en = 1;
+	popts->twoT_en = 0;
 	popts->threeT_en = 0;
 
 	/*