Change order of sai's dma-names to clearn up below DTB_CHECK warning.

   arch/arm64/boot/dts/freescale/fsl-ls1012a-frdm.dtb: sai@2b50000: dma-names:1: 'tx' was expected
   arch/arm64/boot/dts/freescale/fsl-ls1012a-frdm.dtb: sai@2b60000: dma-names:1: 'tx' was expected
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>