arm64: dts: imx8mm: Change SDMA1 ahb clock for imx8mm

arm64: dts: imx8mm: Change SDMA1 ahb clock for imx8mm

BugLink: https://bugs.launchpad.net/bugs/1861090
commit 24a572bf67994223e722cadfe663e15ba221882a upstream.

Using SDMA1 with UART1 is causing a "Timeout waiting for CH0" error.
This patch changes to ahb clock from SDMA1_ROOT to AHB which
fixes the timeout error.

Fixes:  a05ea40eb384 ("arm64: dts: imx: Add i.mx8mm dtsi support")
Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>