apalis-tk1: fix setting fdtfile value

s/fdt-module/fdt_module/g, as we don't use dash in fdt_file anymore.

Fixes: 4c63a601("apalis-tk1: support v1.2 hardware revision")
Signed-off-by: Igor Opaniuk <igor.opaniuk@toradex.com>
diff --git a/configs/apalis-tk1_defconfig b/configs/apalis-tk1_defconfig
index db66d68..42e320e 100644
--- a/configs/apalis-tk1_defconfig
+++ b/configs/apalis-tk1_defconfig
@@ -11,7 +11,7 @@
 CONFIG_FIT=y
 CONFIG_OF_SYSTEM_SETUP=y
 CONFIG_BOOTDELAY=1
-CONFIG_BOOTCOMMAND="setenv fdtfile ${soc}-${fdt-module}-${fdt_board}.dtb && run distro_bootcmd"
+CONFIG_BOOTCOMMAND="setenv fdtfile ${soc}-${fdt_module}-${fdt_board}.dtb && run distro_bootcmd"
 CONFIG_CONSOLE_MUX=y
 CONFIG_SYS_STDIO_DEREGISTER=y
 CONFIG_VERSION_VARIABLE=y