arm64: dts: imx8qm: add lsio ss support

The LSIO SS of MX8QM is exactly the same as MX8QXP. So we can fully
reuse the exist LSIO SS dtsi. Add <soc>-ss-lsio.dtsi with compatible
string updated according to imx8-ss-lsio.dtsi.

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>