arm64: dts: imx93: Fix the dmas entries order

arm64: dts: imx93: Fix the dmas entries order

Per fsl-lpuart.yaml, the dmas and dma-names entries should be
'rx' followed by 'tx'.

Change the order to fix the following schema warning:

imx93-11x11-evk.dtb: serial@44380000: dma-names:0: 'rx' was expected
	from schema $id: http://devicetree.org/schemas/serial/fsl-lpuart.yaml#
imx93-11x11-evk.dtb: serial@44380000: dma-names:1: 'tx' was expected
	from schema $id: http://devicetree.org/schemas/serial/fsl-lpuart.yaml#

Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>