x86/PCI: Constify pci_mmcfg_probes[] array

The pci_mmcfg_probes[] array is only ever read, therefore make it const.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NIngo Molnar <mingo@kernel.org>

arch/x86/pci/mmconfig-shared.c

@@ -306,7 +306,7 @@ struct pci_mmcfg_hostbridge_probe {
 	const char *(*probe)(void);
 };
 
-static struct pci_mmcfg_hostbridge_probe pci_mmcfg_probes[] __initdata = {
+static const struct pci_mmcfg_hostbridge_probe pci_mmcfg_probes[] __initconst = {
 	{ 0, PCI_DEVFN(0, 0), PCI_VENDOR_ID_INTEL,
 	  PCI_DEVICE_ID_INTEL_E7520_MCH, pci_mmcfg_e7520 },
 	{ 0, PCI_DEVFN(0, 0), PCI_VENDOR_ID_INTEL,