arm64: dts: imx8qm: Correct SCU clock controller's compatible property

The fsl,scu.txt dt-binding documentation explicitly mentions
that the compatible string should be either "fsl,imx8qm-clock"
or "fsl,imx8qxp-clock", followed by "fsl,scu-clk".  Also, i.MX8qm
SCU clocks and i.MX8qxp SCU clocks are really not the same, so
we have to set the compatible property according to SoC name.
Let's correct the i.MX8qm clock controller's compatible property
from
"fsl,imx8qxp-clk", "fsl,scu-clk"
to
"fsl,imx8qm-clk", "fsl,scu-clk" .

Fixes: f2180be1 ("arm64: dts: imx: add imx8qm common dts file")
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>