arm64: dts: rockchip: fix dwmmc clock name for px30

arm64: dts: rockchip: fix dwmmc clock name for px30

An experimental test with the command below gives this error:
px30-evb.dt.yaml: dwmmc@ff390000: clock-names:2:
'ciu-drive' was expected

'ciu-drv' is not a valid dwmmc clock name,
so fix this by changing it to 'ciu-drive'.

make ARCH=arm64 dtbs_check
DT_SCHEMA_FILES=Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Link: https://lore.kernel.org/r/20200110161200.22755-1-jbx6244@gmail.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>