ARM: dts: rockchip: move mmc aliases to board dts on rk3066/rk3188

As suggested by Arnd Bergmann, the newly added mmc aliases
should be board specific, so move them from the general dtsi
to the individual boards.

Suggested-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Link: https://lore.kernel.org/r/20210520091822.28491-1-jbx6244@gmail.com


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