Revert "Revert "cmd: pxe_utils: Check fdtcontroladdr in label_boot""

This reverts commit ed625118.

Superseded by "cmd: pxe_utils: Limit fdtcontroladdr usage to non-fitImage"
which is less heavy-handed approach and retains part of the original
behavior for non-fitImage.

Signed-off-by: Marek Vasut <marex@denx.de>
Acked-by: Neil Armstrong <neil.armstrong@linaro.org>