s390/pci: Fix duplicate pci_dev_put() in disable_slot() when PF has child VFs

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

s390/pci: Fix duplicate pci_dev_put() in disable_slot() when PF has child VFs

With commit bcb5d6c76903 ("s390/pci: introduce lock to synchronize state

of zpci_dev's") the code to ignore power off of a PF that has child VFs

was changed from a direct return to a goto to the unlock and

pci_dev_put() section. The change however left the existing pci_dev_put()

untouched resulting in a doubple put. This can subsequently cause a use

after free if the struct pci_dev is released in an unexpected state.

Fix this by removing the extra pci_dev_put().