xen/pci: prevent infinite loop for faulty SR-IOV cards

If a SR-IOV card presents an I/O space inside a BAR the
code will continue to loop on the same card.
This is due to the missing increment of the cycle variable.

Fixes: a1a6d59862 ("pci: split code to size BARs from pci_add_device")
Signed-off-by: Frediano Ziglio <frediano.ziglio@cloud.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Release-Acked-By: Oleksii Kurochko <oleksii.kurochko@gmail.com>

xen/drivers/passthrough/pci.c

@@ -746,6 +746,7 @@ int pci_add_device(u16 seg, u8 bus, u8 devfn,
                     printk(XENLOG_WARNING
                            "SR-IOV device %pp with vf BAR%u in IO space\n",
                            &pdev->sbdf, i);
+                    ++i;
                     continue;
                 }
                 ret = pci_size_mem_bar(pdev->sbdf, idx, NULL,