arch/*/io.h: Add ioremap_wt() to all architectures

Add ioremap_wt() to all arch-specific asm/io.h headers which
define ioremap_wc() locally. These headers do not include
<asm-generic/iomap.h>. Some of them include <asm-generic/io.h>,
but ioremap_wt() is defined for consistency since they define
all ioremap_xxx locally.

In all architectures without Write-Through support, ioremap_wt()
is defined indentical to ioremap_nocache().

frv and m68k already have ioremap_writethrough(). On those we
add ioremap_wt() indetical to ioremap_writethrough() and defines
ARCH_HAS_IOREMAP_WT in both architectures.

The ioremap_wt() interface is exported to drivers.

Signed-off-by: Toshi Kani <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: [email protected]
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Luis R. Rodriguez <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: linux-mm <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

arch/nios2/include/asm/io.h

@@ -46,6 +46,7 @@ static inline void iounmap(void __iomem *addr)
 }
 
 #define ioremap_wc ioremap_nocache
+#define ioremap_wt ioremap_nocache
 
 /* Pages to physical address... */
 #define page_to_phys(page)	virt_to_phys(page_to_virt(page))