powerpc/powernv: Make pnv_ioda_deconfigure_pe() visible

pnv_ioda_deconfigure_pe() is visible only when CONFIG_PCI_IOV is
enabled. The function will be used to tear down PE's associated
mapping in PCI hotplug path that doesn't depend on CONFIG_PCI_IOV.

This makes pnv_ioda_deconfigure_pe() visible and not depend on
CONFIG_PCI_IOV.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>