GE Bx50v3 boards: fix fdt file variable

The CONFIG_DEFAULT_FDT_FILE expects just the file not a full path
as that might vary depending on the variant of Linux distro you
might be using.

Cc: Martin Donnelly <martin.donnelly@ge.com>
Cc: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Acked-by: Fabio Estevam <fabio.estevam@nxp.com>
diff --git a/configs/ge_b850v3_defconfig b/configs/ge_b850v3_defconfig
index 45e5fb1..967ddba 100644
--- a/configs/ge_b850v3_defconfig
+++ b/configs/ge_b850v3_defconfig
@@ -5,7 +5,7 @@
 CONFIG_BOOTDELAY=1
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
 CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE=y
-CONFIG_DEFAULT_FDT_FILE="/boot/imx6q-b850v3.dtb"
+CONFIG_DEFAULT_FDT_FILE="imx6q-b850v3.dtb"
 CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_BOOTZ=y