q35: Remove unused mch_mcfg_base

mch_mcfg_base has been unused since it was added by
  6f1426ab0f ("ich9: APIs for pc guest info")
back in 2013.

Remove it.

Signed-off-by: Dr. David Alan Gilbert <dave@treblig.org>
Reviewed-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

hw/pci-host/q35.c

@@ -662,16 +662,6 @@ static void mch_realize(PCIDevice *d, Error **errp)
                                    OBJECT(&mch->smram));
 }
 
-uint64_t mch_mcfg_base(void)
-{
-    bool ambiguous;
-    Object *o = object_resolve_path_type("", TYPE_MCH_PCI_DEVICE, &ambiguous);
-    if (!o) {
-        return 0;
-    }
-    return MCH_HOST_BRIDGE_PCIEXBAR_DEFAULT;
-}
-
 static Property mch_props[] = {
     DEFINE_PROP_UINT16("extended-tseg-mbytes", MCHPCIState, ext_tseg_mbytes,
                        16),

include/hw/pci-host/q35.h

@@ -181,8 +181,6 @@ struct Q35PCIHost {
 #define MCH_PCIE_DEV                           1
 #define MCH_PCIE_FUNC                          0
 
-uint64_t mch_mcfg_base(void);
-
 /*
  * Arbitrary but unique BNF number for IOAPIC device.
  *