ARM: dts: at91: sama7g5: Swap `rx` and `tx` for `i2c` nodes

Swap `rx` and `tx` for the `dma-names` property of the `i2c` nodes
in order to maintain consistency across Microchip/Atmel SoC files.

Signed-off-by: Sergiu Moga <sergiu.moga@microchip.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20220310114553.184763-2-sergiu.moga@microchip.com