CVE-2022-48896 ixgbe: fix pci device refcount leak

In the Linux kernel, the following vulnerability has been resolved:

ixgbe: fix pci device refcount leak

As the comment of pci_get_domain_bus_and_slot() says, it
returns a PCI device with refcount incremented, when finish
using it, the caller must decrement the reference count by
calling pci_dev_put().

In ixgbe_get_first_secondary_devfn() and ixgbe_x550em_a_has_mii(),
pci_dev_put() is called to avoid leak.