net: ethernet: mtk_eth_soc/wed: fix sparse endian warnings

Descriptor fields are little-endian

Fixes: 804775df ("net: ethernet: mtk_eth_soc: add support for Wireless Ethernet Dispatch (WED)")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: David S. Miller <davem@davemloft.net>