MIPS: Use GENERIC_IOMAP

MIPS has a copy of lib/iomap.c with minor alterations, none of which are
necessary given appropriate definitions of PIO_OFFSET, PIO_MASK &
PIO_RESERVED. Provide such definitions, select GENERIC_IOMAP & remove
arch/mips/lib/iomap.c to cut back on the needless duplication.

The one change this does make is to our mmio_{in,out}s[bwl] functions,
which began to deviate from their generic counterparts with commit
0845bb721ebb ("MIPS: iomap: Use __mem_{read,write}{b,w,l} for MMIO"). I
suspect that this commit was incorrect, and that the SEAD-3 platform
should have instead selected CONFIG_SWAP_IO_SPACE. Since the SEAD-3
platform code is now gone & the board is instead supported by the
generic platform (CONFIG_MIPS_GENERIC) which selects
CONFIG_SWAP_IO_SPACE anyway, this shouldn't be a problem any more.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20342/
Cc: linux-mips@linux-mips.org
diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h
index 54c730a..bbbeede 100644
--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -80,6 +80,16 @@ static inline void set_io_port_base(unsigned long base)
 }
 
 /*
+ * Provide the necessary definitions for generic iomap. We make use of
+ * mips_io_port_base for iomap(), but we don't reserve any low addresses for
+ * use with I/O ports.
+ */
+#define HAVE_ARCH_PIO_SIZE
+#define PIO_OFFSET	mips_io_port_base
+#define PIO_MASK	IO_SPACE_LIMIT
+#define PIO_RESERVED	0x0UL
+
+/*
  * Thanks to James van Artsdalen for a better timing-fix than
  * the two short jumps: using outb's to a nonexistent port seems
  * to guarantee better timings even on fast machines.
@@ -172,11 +182,6 @@ static inline void *isa_bus_to_virt(unsigned long address)
 extern void __iomem * __ioremap(phys_addr_t offset, phys_addr_t size, unsigned long flags);
 extern void __iounmap(const volatile void __iomem *addr);
 
-#ifndef CONFIG_PCI
-struct pci_dev;
-static inline void pci_iounmap(struct pci_dev *dev, void __iomem *addr) {}
-#endif
-
 static inline void __iomem * __ioremap_mode(phys_addr_t offset, unsigned long size,
 	unsigned long flags)
 {