am335x: Update timings for the beaglebone again

After further testing we can run DDR at 400MHz so update the timings
again.

Tested-by: Koen Kooi <koen@dominion.thruhere.net>
Signed-off-by: Tom Rini <trini@ti.com>
diff --git a/board/ti/am335x/board.c b/board/ti/am335x/board.c
index 12620bb..b371376 100644
--- a/board/ti/am335x/board.c
+++ b/board/ti/am335x/board.c
@@ -379,7 +379,7 @@
 		config_ddr(303, MT41J128MJT125_IOCTRL_VALUE, &ddr3_data,
 			   &ddr3_cmd_ctrl_data, &ddr3_emif_reg_data, 0);
 	else if (board_is_bone_lt())
-		config_ddr(303, MT41K256M16HA125E_IOCTRL_VALUE,
+		config_ddr(400, MT41K256M16HA125E_IOCTRL_VALUE,
 			   &ddr3_beagleblack_data,
 			   &ddr3_beagleblack_cmd_ctrl_data,
 			   &ddr3_beagleblack_emif_reg_data, 0);