ssb: Fix probing of PCI cores if PCI and PCIE core is available

This will make sure that always the correct core is selected, even if
there are both a PCI and PCI-E core on a PCI or PCI-E card.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>