Revert "cmd: pxe_utils: Check fdtcontroladdr in label_boot"

With the change here, all extlinux.conf files with only "KERNEL
/fitImage" don't work anymore. One common example of this would be those
files generated by thee Poky/OE WIC bootimg-partition bootloader
partition generator.

This reverts commit d5ba6188.

Reported-by: Neil Armstrong <neil.armstrong@linaro.org>
Reported-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>
Signed-off-by: Tom Rini <trini@konsulko.com>