configs: e850-96: Disable CONFIG_DEFAULT_FDT_FILE

configs: e850-96: Disable CONFIG_DEFAULT_FDT_FILE

Linux kernel should use some separate device tree obtained from another
source anyway. For example the dtb file can be read from /boot directory
in eMMC rootfs partition, either by GRUB or U-Boot. Using U-Boot's
device tree blob to provide it to the kernel (when
CONFIG_DEFAULT_FDT_FILE is set and nobody else overrides this choice)
might lead to undesired effects when booting the OS. For example, if a
user sets "dr_mode" property to "host" value in U-Boot's dts to enable
USB host capabilities in U-Boot, it might confuse usb-conn-gpio driver
in Linux kernel later like this:

    platform connector: deferred probe pending: usb-conn-gpio:
    failed to get role switch

Disable CONFIG_DEFAULT_FDT_FILE option to avoid any possible confusion.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>