dt-bindings: rockchip-dw-mshc: rename RK1108 to RV1108

Rockchip finally named the SOC as RV1108, so change it.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>