sfc: remove duplicate up_write on VF filter_sem

Somehow two copies of the line 'up_write(&vf->efx->filter_sem);' got into
 efx_ef10_sriov_set_vf_vlan().  This would put the mutex in a bad state and
 cause all subsequent down attempts to hang.

Fixes: 671b53ee ("sfc: Ensure down_write(&filter_sem) and up_write() are matched before calling efx_net_open()")
Signed-off-by: NEdward Cree <ecree@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/ef10_sriov.c

@@ -661,8 +661,6 @@ int efx_ef10_sriov_set_vf_vlan(struct efx_nic *efx, int vf_i, u16 vlan,
 		up_write(&vf->efx->filter_sem);
 		mutex_unlock(&vf->efx->mac_lock);
 
-		up_write(&vf->efx->filter_sem);
-
 		rc2 = efx_net_open(vf->efx->net_dev);
 		if (rc2)
 			goto reset_nic;