arm64: dts: imx8mp: correct sdma1 clk setting

Correct sdma1 ahb clk, otherwise wrong 1:1 clk ratio will be chosed so
that sdma1 function broken. sdma1 should use 1:2 clk, while sdma2/3 use
1:1.

Fixes: 6d9b8d20

 ("arm64: dts: freescale: Add i.MX8MP dtsi support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>