mips: use the the PCI controller's io_map_base

commit eab90291d35438bcebf7c3dc85be66d0f24e3002
(mips: switch to GENERIC_PCI_IOMAP)
failed to take into account the PCI controller's
io_map_base for mapping IO BARs.
This also caused a new warning on mips.

Fix this, without re-introducing code duplication,
by setting NO_GENERIC_PCI_IOPORT_MAP
and supplying a mips-specific __pci_ioport_map.

Reported-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

arch/mips/Kconfig

@@ -2356,6 +2356,7 @@ config PCI
 	depends on HW_HAS_PCI
 	select PCI_DOMAINS
 	select GENERIC_PCI_IOMAP
+	select NO_GENERIC_PCI_IOPORT_MAP
 	help
 	  Find out whether you have a PCI motherboard. PCI is the name of a
 	  bus system, i.e. the way the CPU talks to the other stuff inside

arch/mips/lib/iomap-pci.c

@@ -10,8 +10,8 @@
 #include <linux/module.h>
 #include <asm/io.h>
 
-static void __iomem *ioport_map_pci(struct pci_dev *dev,
-                                     unsigned long port, unsigned int nr)
+void __iomem *__pci_ioport_map(struct pci_dev *dev,
+			       unsigned long port, unsigned int nr)
 {
 	struct pci_controller *ctrl = dev->bus->sysdata;
 	unsigned long base = ctrl->io_map_base;