arm64: dts: imx93: use FSL_EDMA_RX for rx channel

Use FSL_EDMA_RX for dma rx channel bitmask, which is intuitive.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>