include: dt-bindings: rockchip: mark RK_FUNC defines as deprecated

The defines RK_FUNC_1, RK_FUNC_2, RK_FUNC_3 and RK_FUNC_4
are no longer used. Mark them as "deprecated"
to prevent that someone start using them again.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Link: https://lore.kernel.org/r/20191015205852.4200-2-jbx6244@gmail.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>