arm64: dts: rockchip: fix pcie-refclk frequency on rk3588 tiger

arm64: dts: rockchip: fix pcie-refclk frequency on rk3588 tiger

The clock-generator of course only produces a 100MHz clock rate,
not 1GHz.

Signed-off-by: Heiko Stuebner <heiko.stuebner@cherry.de>
Reviewed-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>
Link: https://lore.kernel.org/r/20240423114635.2637310-1-heiko@sntech.de
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
[ upstream commit: 0eb2a93518fb4728bd1d55fcd3b57fce4797ef1d ]

(cherry picked from commit b574cbafae976cf508692088944e45c9764c0048)