clk: rockchip: Add appropriate arch dependencies

There's no point offering support for 32-bit platforms to users
configuring a 64-bit kernel - and vice-versa - unless they are
explicitly interested in compile-testing.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/72abb0f794b8ed77e274e8ee21c22e0bd3223dfd.1603710913.git.robin.murphy@arm.com


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