arm64: dts: imx8qxp: move scu pd node before scu clock node

SCU clock depends on SCU Power domain. Moving scu pd node before
scu clock can save a hundred of defer probes of all system devices
which depends on power domain and clocks.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>