mx53loco: Change 'fdt_file' dynamically

Since kernel 3.15 there are two dtb's for the imx53-qsb board:

imx53-qsb.dtb - For the boards with DA9053 PMIC
imx53-qsrb.dtb - For the boards with MC34708 PMIC

Change the 'fdt_file' dynamically, so that the correct dtb can be used depending
on the board variant.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Otavio Salvador <otavio@ossystems.com.br>

board/freescale/mx53loco/mx53loco.c

@@ -242,6 +242,8 @@ static int power_init(void)
 		if (!p)
 			return -ENODEV;
 
+		setenv("fdt_file", "imx53-qsb.dtb");
+
 		/* Set VDDA to 1.25V */
 		val = DA9052_BUCKCORE_BCOREEN | DA_BUCKCORE_VBCORE_1_250V;
 		ret = pmic_reg_write(p, DA9053_BUCKCORE_REG, val);
@@ -283,6 +285,8 @@ static int power_init(void)
 		if (!p)
 			return -ENODEV;
 
+		setenv("fdt_file", "imx53-qsrb.dtb");
+
 		/* Set VDDGP to 1.25V for 1GHz on SW1 */
 		pmic_reg_read(p, REG_SW_0, &val);
 		val = (val & ~SWx_VOLT_MASK_MC34708) | SWx_1_250V_MC34708;

include/configs/mx53loco.h

@@ -107,7 +107,6 @@
 #define CONFIG_EXTRA_ENV_SETTINGS \
 	"script=boot.scr\0" \
 	"image=zImage\0" \
-	"fdt_file=imx53-qsb.dtb\0" \
 	"fdt_addr=0x71000000\0" \
 	"boot_fdt=try\0" \
 	"ip_dyn=yes\0" \