arm64: dts: imx8mq: Change ahb clock for imx8mq

Set ahb clock on sdma1 to get rid of "Timeout waiting for CH0"
on the imx8mq.

Signed-off-by: Angus Ainslie (Purism) <angus@akkea.ca>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>