arm64: dts: rockchip: replace to "max-frequency" instead of "clock-freq-min-max"

In drivers/mmc/core/host.c, there is "max-freqeuncy" property.
It should be same behavior, So Use the "max-frequency" instead of
"clock-freq-min-max".

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>