ixgbe: fix crash with empty VF macvlan list

The adapter->vf_mvs.l list needs to be initialized even if the list is
empty.  Otherwise it will lead to crashes.

Fixes: a1cbb15c ("ixgbe: Add macvlan support for VF")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Link: https://lore.kernel.org/r/ZSADNdIw8zFx1xw2@kadamSigned-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c

@@ -28,6 +28,9 @@ static inline void ixgbe_alloc_vf_macvlans(struct ixgbe_adapter *adapter,
 	struct vf_macvlans *mv_list;
 	int num_vf_macvlans, i;
 
+	/* Initialize list of VF macvlans */
+	INIT_LIST_HEAD(&adapter->vf_mvs.l);
+
 	num_vf_macvlans = hw->mac.num_rar_entries -
 			  (IXGBE_MAX_PF_MACVLANS + 1 + num_vfs);
 	if (!num_vf_macvlans)
@@ -36,8 +39,6 @@ static inline void ixgbe_alloc_vf_macvlans(struct ixgbe_adapter *adapter,
 	mv_list = kcalloc(num_vf_macvlans, sizeof(struct vf_macvlans),
 			  GFP_KERNEL);
 	if (mv_list) {
-		/* Initialize list of VF macvlans */
-		INIT_LIST_HEAD(&adapter->vf_mvs.l);
 		for (i = 0; i < num_vf_macvlans; i++) {
 			mv_list[i].vf = -1;
 			mv_list[i].free = true;