PCI: Export pci_dev_lock()

Commit e3a9b121

 ("PCI: Export pci_dev_trylock() and pci_dev_unlock()")
already exported pci_dev_trylock()/pci_dev_unlock() however in some
circumstances such as during error recovery it makes sense to block
waiting to get full access to the device so also export pci_dev_lock().

Link: https://lore.kernel.org/all/20210928181014.GA713179@bhelgaas/
Acked-by: Pierre Morel <pmorel@linux.ibm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>