arm64: dts: imx8mq: Fix the fsl,imx8mq-sdma compatible string

Fix a typo in the compatible string

Signed-off-by: Angus Ainslie (Purism) <angus@akkea.ca>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>