net: ethernet: mtk_eth_soc: fix mask of RX_DMA_GET_SPORT{,_V2}

The bitmasks applied in RX_DMA_GET_SPORT and RX_DMA_GET_SPORT_V2 macros
were swapped. Fix that.

Reported-by: Chen Minqiang <ptpt52@gmail.com>
Fixes: 160d3a9b

 ("net: ethernet: mtk_eth_soc: introduce MTK_NETSYS_V2 support")
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://lore.kernel.org/r/YzMW+mg9UsaCdKRQ@makrotopia.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>