PCI: switchtec: Fix an error handling path in switchtec_pci_probe()

The commit in Fixes changed the logic on how resources are released and
introduced a new switchtec_exit_pci() that need to be called explicitly in
order to undo a corresponding switchtec_init_pci().

This was done in the remove function, but not in the probe.

Fix the probe now.

Fixes: df254611 ("PCI: switchtec: Fix stdev_release() crash after surprise hot remove")
Link: https://lore.kernel.org/r/01446d2ccb91a578239915812f2b7dfbeb2882af.1703428183.git.christophe.jaillet@wanadoo.fr


Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>