MC_CMD_LOOPBACK_XGMII
EFX_STATIC_ASSERT(MC_CMD_LOOPBACK_XGMII == EFX_LOOPBACK_XGMII);
EFX_STATIC_ASSERT(MC_CMD_LOOPBACK_XGMII == EFX_LOOPBACK_XGMII);
EFX_STATIC_ASSERT(MC_CMD_LOOPBACK_XGMII == EFX_LOOPBACK_XGMII);