bnx2x: avoid null pointer dereference when enabling SR-IOV

Fixed NULL pointer dereference when dynamically activating SR-IOV after vf
database failed to be allocated in probe stage (for example due to no ARI
support in pci hub).

Signed-off-by: Michal Kalderon <michals@broadcom.com>
Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.c

@@ -3114,6 +3114,11 @@ int bnx2x_sriov_configure(struct pci_dev *dev, int num_vfs_param)
 {
 	struct bnx2x *bp = netdev_priv(pci_get_drvdata(dev));
 
+	if (!IS_SRIOV(bp)) {
+		BNX2X_ERR("failed to configure SR-IOV since vfdb was not allocated. Check dmesg for errors in probe stage\n");
+		return -EINVAL;
+	}
+
 	DP(BNX2X_MSG_IOV, "bnx2x_sriov_configure called with %d, BNX2X_NR_VIRTFN(bp) was %d\n",
 	   num_vfs_param, BNX2X_NR_VIRTFN(bp));