vf610twr: Fix typo in DRAM init

This commit fixes a typo in vf610twr DRAM init that was causing a hang in
U-Boot for the Vybrid Tower. This typo was introduced in commit 3f353cec
(vf610: refactor DDRMC code).

Signed-off-by: Anthony Felice <tony.felice@timesys.com>
Reviewed-by: Fabio Estevam <fabio.estevam@freescale.com>

board/freescale/vf610twr/vf610twr.c

@@ -108,7 +108,7 @@ int dram_init(void)
 		.trcd_int          = 6,
 		.tras_lockout      = 0,
 		.tdal              = 12,
-		.bstlen            = 0,
+		.bstlen            = 3,
 		.tdll              = 512,
 		.trp_ab            = 6,
 		.tref              = 3120,