sh64: Kill off unused fixed I/O mapping window.

This was reworked some time ago to go through fixmaps instead, leaving
the range itself unused. As such, kill off the remaining references and
hand over the remaining space for fixmaps directly. This also makes it
possible to simplify the vmalloc fault case as we no longer have to care
about the special section.

Signed-off-by: Paul Mundt <[e-mail]>

arch/sh/include/asm/fixmap.h

···
 #ifdef CONFIG_SUPERH32
 #define FIXADDR_TOP	(P3_ADDR_MAX - PAGE_SIZE)
 #else
-#define FIXADDR_TOP	(0xff000000 - PAGE_SIZE)
+#define FIXADDR_TOP	((unsigned long)(-PAGE_SIZE))
 #endif
 #define FIXADDR_SIZE	(__end_of_fixed_addresses << PAGE_SHIFT)
 #define FIXADDR_START	(FIXADDR_TOP - FIXADDR_SIZE)

arch/sh/include/asm/pgtable_64.h

···
 #define pte_unmap(pte)		do { } while (0)
 
 #ifndef __ASSEMBLY__
-#define IOBASE_VADDR	0xff000000
-#define IOBASE_END	0xffffffff
-
 /*
  * PTEL coherent flags.
  * See Chapter 17 ST50 CPU Core Volume 1, Architecture.

arch/sh/mm/fault_64.c

···
 	tsk = current;
 	mm = tsk->mm;
 
-	if ((address >= VMALLOC_START && address < VMALLOC_END) ||
-	    (address >= IOBASE_VADDR  && address < IOBASE_END)) {
+	if ((address >= VMALLOC_START && address < VMALLOC_END)) {
 		if (ssr_md)
 			/*
 			 * Process-contexts can never have this address