tegra: clean-up useless define

Wondering what exactly that one should bring (;-p). Looks like a remnant of the last commit

783e6a72
kconfig: move CONFIG_OF_* to Kconfig

Signed-off-by: Marcel Ziswiler <marcel@ziswiler.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>