powerpc/powernv: Mark pnv_pci_init_ioda2_phb() as __init

Mark pnv_pci_init_ioda2_phb() as __init.  It is called only from an
init function (pnv_pci_init()), and it calls an init function
(pnv_pci_init_ioda_phb()):

    pnv_pci_init                # init
      pnv_pci_init_ioda2_phb    # non-init
	pnv_pci_init_ioda_phb   # init

This should fix a section mismatch warning.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powernv/pci-ioda.c

@@ -1266,7 +1266,7 @@ void __init pnv_pci_init_ioda_phb(struct device_node *np,
 		opal_pci_set_pe(phb_id, 0, 0, 7, 1, 1 , OPAL_MAP_PE);
 }
 
-void pnv_pci_init_ioda2_phb(struct device_node *np)
+void __init pnv_pci_init_ioda2_phb(struct device_node *np)
 {
 	pnv_pci_init_ioda_phb(np, 0, PNV_PHB_IODA2);
 }